SAR: When you say the cocking handle is wrong, what do you mean?

Visser: In the end we made it underneath, so that the left or right handed person could use it easily. Anyway, Gene got interested in other things, and I hired Hans Sturtz, a German who worked for Gene Stoner. He was fantastic at making things….he worked for us in Holland, and we changed the Stoner rifle in various ways, small things, but important, like a good folding stock – one that locks. We made a good bipod too, a sturdy bipod, one that locks on the gun. I kept all of the documentation about what we did. We made a barrel with flutes, a thicker barrel, and we arranged for the sling swivels on the right place.

SAR: This is the Stoner 63 we are discussing? Let me go get some examples from the vault. (Dan gets some Stoner 63 and 63As to put on the table for Henk to point out things.)

Visser: Actually the 63A but improved. We did several things for the 63A. This was now the 63A1 when we were done with it. As I said, we improved the bipod and made it mount on the rifle, which was my idea. In the beginning, Gene Stoner didn’t have a flash hider with the right dimensions for the international rifle grenade launching requirements. The original CETME was even missing that by design. They just had a barrel sticking out making a hell of a flash, and noise. I designed the flashhider for the CETME (G3). We changed the Stoner 63A to be able to fire Rifle Launched Grenades (RLG), a very important feature even today in many armies. We changed location of the charging handle, the bipod, the stock, and many other minor changes.

SAR (Dolf): Henk, I thought that originally you were involved with the AR-10, with the 7.62 Stoner rifle?

Visser: No, Dolf, I have heard this before but I had nothing to do with that. The AR-10 was our competitor, the government plant Artillerie Inrichtingen (AI) at Hembrug, in Holland. They got so upset that we had the Stoner 63A license – first we had the CETME rifle then the Stoner – that when the Director of AI read in TIME Magazine about this lightweight rifle from ArmaLite, he and his secretary got on a plane and flew to Costa Mesa to make a deal on the AR-10. He was not liked by the Dutch generals because of the way he treated them. In reality, the AR-10 was a fantastic rifle for 7.62 NATO. Director Jungeling invited all the top generals to his plant and they were getting coffee and cake, and while they were eating he reached next to his chair and holds up an AR-10 and announces, “Gentlemen, this is your new rifle! This will be the future!” Those generals decided at that moment in their minds that nobody was going to adopt the AR-10. They didn’t want to be told by a civilian what would be the new Army rifle. He killed it with that. It’s a very sad story because it was a good rifle. They wanted to do their own testing and make their own decision and like most generals, they do not like anyone telling them what they will have for weapons.

SAR: You had the rights to the Stoner 63 outside of the United States?

Visser: Outside of United States and Canada. We had a very optimistic view of our opportunities because we and Cadillac Gage thought that the US Marines would adopt the system. We took the Stoner Rifle to Ecuador, Chile, Sweden, Norway, Denmark, Germany and, Israel. I went everywhere. We spent millions, and I told the top people in my company, “This is it. This is what the soldiers want.” I never told the customers that – I simply showed them the quality and let them test the rifle. Standardization, a cheap machine gun…the main parts are all the same. Maybe I overdid it a little bit at times. We had the Inspector General of all of the forces in Holland and his Royal Highness Prince Bernard; he had seen it and liked it, and he tried to push it in NATO. Again, I think maybe there was too much support in this way, these guys all wanted to do it themselves and make their own decisions. I was instrumental in the standardization of the rifle grenades as well. Because of me, all of the rifles have the flash hider with the 22mm diameter. I was close with MECAR in Belgium, and we developed a whole series of rifle grenades, including a new small hollow charge which would puncture a 5cm hole in a steel plate at 160 meters.

SAR: So this was a shaped charge system. What was the launching platform – bullet trap, bullet through or launching blank?

Visser: It was a special blank cartridge at the beginning. We had, even for the Stoner, a short magazine that was colored green that could be loaded with this gas cartridge, so that there would be no mistake of putting a live cartridge in the gun.

SAR: Did you get any sales of the Stoner 63A1 in the countries you just mentioned?

Visser: The biggest thing was that the United States Marines were going to adopt it. I was at Quantico almost weekly, and they wanted these, so after the first lots of prototypes they ordered 3,000 or so from Cadillac Gage and shipped the Stoners to Vietnam. They wanted a live combat environment to test them. The Stoner was very successful and the Marines liked it. Then the U.S. Army stepped in and said, “No. We will all have the same weapons. You take the M16.” The Marines got mad, and talked about bent barrels and this and that, and the cocking handle they did not like and the rifles needed a heavier barrel, etc. We were offering this gun that we demonstrated as the future U.S. Marine weapon. We really pushed that, you know? Because who was this tiny little company in Holland, and Cadillac Gage was not known either: they made a few armored cars. Nothing to show manufacturing ability with small arms, but the Marines with Stoners, that was another story and it was our sales pitch to our customers.

Gene Stoner was very bitter about many of the issues that occurred then. In the Stoner 63 rifle he had tried to fix what he saw as the problems in the M16, which was also his design originally.

The big blow was when the decision came that the U.S. Marines were not going to take the Stoner system. This made it difficult for us, because the people we were trying to sell it to thought something must be defective with the guns since the U.S. was not adopting it. I had sold 12 to Singapore after a demonstration and sold some to Thailand, Japan and South Korea. We were a nice company, we didn’t bribe anybody. The same in the Philippines. I still remember the offer for the Philippines. We had trained them so that they could work on the guns themselves. It was a $35 million deal. Then Colt got in and they got the order instead for $58 million. Their agent had better “contacts” – almost $20 million extra above what our program was. I was with the top man there, the commissioner, and if I had said that we could raise it to $55 million or whatever, we would have had that deal. But that would have never occurred to me. The same thing happened on the deal in South Korea.

The Stoner is an excellent weapon, and the only complaint I ever had was that if the soldiers have the rifle, and then they give the company armorer some cigarettes or something, they’ll quickly have a belt-fed and a heavier barrel, and before you know it everyone in the whole group has a machine gun. (Visser laughs.)

SAR: That’s a complaint? If they trained a platoon with all belt fed Stoners, it would have been pretty formidable.

Visser: Yes, but these armies aren’t trained that way. Riflemen should be riflemen, and the machine gun is restricted to certain personnel with specific machine gun jobs. It would have been very simple to make things so that you couldn’t make a machine gun out of a rifle, but that would get rid of one of the beautiful things about the Stoner – the adaptability. The only complaint I ever received was that it was too easy to make a machine gun out of it.

SAR: Henk, you were involved in many of the post World War II arms deals. What about the surplus deals?

Visser: I got some surplus 20mm ammo from our Air Force and I sold it to Israel. I worked with Tom Nelson’s company and went on some trips with him, but we were not very successful in obtaining surplus guns.

SAR: Was there any surplus in your time in Vietnam?

Visser: Only the RPGs and other items we discussed earlier. Of course there were much more US military leftovers from Vietnam that were surplused out, but not through our company. I should tell you that I was given the rank of Colonel in the US Army so that I had an ID card. If you got captured by the North Vietnamese, the US Army figured that an officer would be treated better. I still have the ID today. (Henk shows us a Vietnam era US Military ID card with his picture and the rank of Colonel.) We wanted to know how the testing went with the 3,000 guns for Vietnam, but secondly we had to be involved in the MECAR rifle grenades. The Marines were very interested in these rifle grenades, the shaped charges that punched 5cm holes. There was one demonstration where the armored plate was at 160 meters, and as I was a good shot, I could stand there and whop it, and they could see the hole was there. I came upon the idea of mini hand grenades then. In Vietnam, I saw the soldiers go out with only two hand grenades, and if the grenades got wet then they had to be destroyed. With the help of MECAR, we made very small hand grenades and the inside was ribbed in little squares. We used RDX instead of the normal high-explosive. I designed a special short ring that you couldn’t pull, you had to twist it, and then you could get it out. This prevented a lot of accidents. I had a special detonator made by Dynamit Nobel and we sealed the grenades in plastic so you’d have a bandolier with ten mini hand grenades. This weighed as much as two standard hand grenades giving the soldiers a lot of waterproof hand grenades for their missions. I also had them make an aluminum tail with an old-type beer bottle closer; you could stick the hand grenade on there and close that. There was a thin wire, so when you fired it from the rifle, the wire would break and the lever would jump off and at 200 meters you had an explosion.

Then MECAR said, “Nice, but let’s make a rifle grenade that’s just the same in arming, but the standard size.” We also had parachute flares. Then there was a request from the Americans and they said, “Listen, we have had cases where we bombed our own people in the deep jungle cover. We want a flare that goes through the canopy and explodes at 100 meters with a big flash and a brown cloud.” They wanted a test quantity of 200 or so, and three weeks later they were on a plane from Germany to Vietnam for testing. It was really successful; there was a big flash and a bang after it exited the jungle canopy. We were working to design a bullet trap in the grenade tail so you could fire with live rounds. Around that time the owners of MECAR decided to sell the whole shebang to an American company. I had a contract with them that said I received a commission on everything that was sold, regarding the rifle grenades and such. They tried to talk me out of it, and I said, “Gentlemen. You’ve just told me that I am going to make millions from these mini-grenades, but give me one hundred thousand dollars and it’s yours.” I wanted out of the company and the new owners. A lot of yak-yak and I got my hundred thousand dollars.

SAR: But not the millions in the future…

Visser: No, I would get none of that. The Marines bought a lot of those rifle grenades, and they tested them and decided to adopt them. Again the same thing happened. The U.S. Army was working on the 40mm launchers and they didn’t want the Marines to have something else. The Marines adopted the 40mm, not our multi-purpose hand and rifle grenades.

SAR: That sounds like the end of the Stoner 63 and MECAR projects. Where did you go from there?

Visser: We were into developing a “breakup” training round. It was an idea that I had in Germany after seeing how they had to have tremendous ranges when they were shooting at air targets. We had a plastic bullet with compressed iron powder parts in it that gave the same recoil – everything the same as a ball round, but it caught the rifling and because of the plastic jacket, after 50 meters or so, it would burst and there was just a cloud of powder. What they also wanted to test was putting a round that wouldn’t function in the magazines; something which would cause a stoppage. It was for the soldiers learning to fix the stoppage. We sold millions to the Germans. Really, many millions in numerous calibers as it turned out. This ammo functioned perfectly in the German 20mm gun and the twin 20mm AA guns.

They had thousands of these twin-barreled 20mm guns used for AA defense and the troops had to train with them. For training purposes, a plane came flying past with the target sack. They had to aim and they fired like mad and it was really something exciting to see: a whole row of twenty twin 20mm guns. From there we went to the 40mm Bofors round 40 l 60 and 70, also with the break up projectile.

One problem occurred when the Dutch Navy wanted the 40mm Bofors too. They went out and shot it at sea, but there was so much wind out there that the powder would blow back and immediately started rusting the ship. “Oh my God, our beautiful ship! You are ruining our beautiful ships” they cried. (Laughter.) For land based use, though, we sold a lot of these.

Around that time the Swiss company Oerlikon asked me to come and work for them. Singapore asked me to get them 120 20mm cannons for the armored cars they bought from Cadillac Gage. I just walked in to Oerlikon and said, “They want an order from you for 120 cannons.” Oerlikon couldn’t believe it. They had never done much business in the Far East, only Japan. I got the offer and flew out to Singapore. They looked at the prices and thought it was ok, and they went up to the boss, who had a Dutch name, and he signed the contract. I was amazed. I came back and walked into Oerlikon and said, “Here’s your contract.” They almost fell over. After the war they hadn’t had any big contracts like that, 120 20mm guns. The big boss said to me, “What do you want as a commission?” I hadn’t even thought about it. I thought, “Maybe one percent? Do I have the guts to ask for two percent?” Then the boss says, “Is six percent enough?” I got a million Swiss francs commission, and that was the first time I’d ever done anything like that. I started working for them and became the boss for the whole Far East. I sold the South Koreans all of their 35mm AA guns, and also sold to Taiwan, Singapore, Malaysia, and Thailand. That made me a rich man, you know, because besides the big salary they paid me a two percent commission as well. When you get a $900 million order, that’s really something. (Laughter). I was with Oerlikon for about fifteen years, from 1975 until around 1990.

SAR: Not bad for a little Dutch kid who started his cannon ammunition career making 20mm detonators while a slave laborer in a German prison.

Visser: Yes, a very, very, long way from that.

SAR: What are you working on today?

Visser: I spend most of my time working on restoration of historical firearms, major projects to save many of these works of art. There was a big restoration project in Russia. I came to Russian in 1988 with Dr. Arne Hoff, the director of the Tojhuseet museum in Copenhagen. Even before the war, it was known there were many historical Dutch guns in the Kremlin Armory. We went there, and we were received well but they didn’t even want to give us their last names. It was forbidden to give your last name to a foreigner. I liked them, and they liked me, and we got off on good footing. Each time I came there, I brought them suitcases full of Dutch specialties of coffee, “cup-a-soup” packets, an electric water heater, and 200w light bulbs. They had 40w light bulbs in the depot and you couldn’t see anything. I brought them nice mugs to drink from, and we had a very good relationship.

I knew all the guns they had, and they had about 350 beautiful guns, of which 120 needed serious care. Pieces were broken off, pieces to be repaired, and I asked, “Why don’t you restore them? You have a lot of wonderful pieces here.” They said, “We have no money to do this, Russian things must come first.” I said I would do it and would pay for it. It took two years of negotiation, and I became friends with the Minister of Culture, who must have studied at an American university because he spoke fluent English. They eventually let 120 guns go to Holland where I could have them restored. We had the best restorer in the world for antique arms, Herman Prummel, he can do anything. I thought it would be half-year project, but it took two and a half years to finish. In the meantime, a good friend of mine, Helena Yablonskaya, wrote up all the Dutch guns in Russia; about 120 at the Kremlin Armory, some at the Historical Museum, some at St. Petersburg’s Hermitage, 350 in all. In the series of my books, there is one book about all of those.

SAR: It sounds like you are very dedicated now to restoring these historical Dutch firearms.

Visser: Yes, very much so. I am full of crazy stories on this. When I was younger, before the war, our high school made day trips to different places. One of the trips was to Emden in North Germany and there was an armory in the Rathouse with lots of suits of armor and guns and pistols. The first battle with the Spaniards in our Eighty Years War was in 1568 in ‘t Heiligerlee, a village near Groningen. There was a wooden case closed with mesh steel wire, and inside it were musket balls from the first battle to get rid of the Spaniards. We had a Nazi guard with us in a black uniform, and when he wasn’t looking I took my pocketknife and lifted up the steel wire and stole one musket ball. I still have it today. (Laughter.)

Emden was flattened during the war and I always wanted to go back. I went to the Meppen Army testing grounds nearby, but I never got to go back to Emden. Finally, about a year and a half ago I go with Herman Prummel who told me that a lot of pistols were rotting away in the depot. I went over there….and it was horrible. There were the most beautiful Dutch wheellock pistols full of wormholes, half the stock gone, and the metal cleaned with emery paper. My big mistake was not to take the whole pile for an offer of 50,000 euros because they’re never going to show this stuff, but I said, “Why don’t you restore them?” They said they had no money, so I said I’d do it. They said, “Why don’t you take them? We’ll talk to the director, and come back in two weeks.” So I came back in two weeks and instead of having 10 ready, they had 50. We took all 50, and it took more than a year for Herman Prummel to restore them. They are in fantastic condition now. Fortunately, they had saved all the metal parts that had fallen off. If the buttstock had been eaten, they still had the metal ring. Those Dutch wheellock pistols were very light and elegant. These are at my house right now, waiting for the museum to open. We are now working on a catalogue with pictures of them.

I guess that my passion today is the works of art that are in these old firearms. I have spent a lot of time making them whole again.

SAR: Henk, I want to thank you for sharing these stories with SAR’s readers.

Visser: Yes, I have enjoyed this, and I hope to come to the SHOT show and see old friends.

We discussed many more stories of the old days and the arms trade, as well as current restoration projects that Henk Visser is involved in, but those must wait for another day. – Dan

In August of 2001, HK did their desert testing of the new MG43 machine gun system in 5.56 x 45mm. As usual, this was a torture test of the testers as well as the weapons. The 116º f ambient temperature does not begin to describe the actual temperatures out in the noonday sun. The dust and sand is everywhere, gets into everything, and is a great environment for finding out where the weak points in a system are. We did not find many in the MG43. There were far more weak points in your faithful correspondent than in anything that HK tested on the Cibola Dust Range those weeks in August of 2001.

The United States is not the only country that has requirements for a lightweight belt fed weapon. While this writer is a dyed in the wool, true believer, old school (Readers may insert more clichés) curmudgeon on the caliber issue- I believe that a machine gun should be in 30 caliber in order to perform all of the functions that a machine gunner needs it to do out to 1200 meters +, there is definitely a demonstrated need for an intermediate belt fed weapon. After Action reports (Yes, those modern day “Lessons Learned” reports) have demonstrated at what short ranges most modern combat happens at, and emphasizes the need for a lightweight, portable, reliable belt fed weapon in a 5.56 caliber, allowing each squad to have a belt fed operator. To this point in time, the FN Minimi / M249 system has been the predominant offering, accepted in many armies around the world. There have been other offerings ranging from the well known HK23 series, to the famed Stoner 63, to the mysterious Israeli Negev, to the very sexy but totally unreliable Spanish Cetme Ameli. I love that Ameli’s miniature MG42 looks, but wouldn’t want to bet the farm on it.

Lately, there have been many more requirements written, reaching for ever lighter weight, and ever more reliable and ergonomic designs. Some of these have moved into the 30 caliber range – 7.62 x 51mm NATO- and there are presently trials that SAR will be bringing you updates on. However, the current offering is in 5.56 x 45 mm NATO.

In this present requirement, the German firm of HK GmbH in Oberndorf has been working on a new weapon, the MG43. SAR was given an early look at this interesting and innovative weapon last year. We were asked to keep this quiet until the new system was unveiled at the NDIA Small Arms Symposium in May of 2002. I have chosen to present the features of this weapon as a photo essay in the issue that will be at the NDIA, and if you read through the captions and look at the photos, you will get a working view of this new design.

HK has taken some things from the old, and added a lot of new features. The goal of the German designers has been to make an extremely reliable system, as usual. And they have succeeded, as usual.

For our testing, the Germans fired 102,000 rounds of US Milspec 5.56x 45 ammunition. There were minor glitches here and there, but the two guns made it through the tests in one piece. It was most amazing to watch the testing cycle- fire a belt, toss the barrel into a barrel of water, slap another barrel on the gun, load a belt, and repeat. Endlessly. The barrels stood up to the rapid temperature changes, as did the MG43 system.

I observed the firers for quite a while to determine the controllability issue- and the MG43 was easy to handle. This is a subjective part of the report- what’s it like to shoot it? Well, the 750rpm cyclic rate is smooth for the weapon, an appropriate compromise between what the end users want for burst hit probability, and what is probably the natural harmonic of the weapon- I suspect it to be just above 500 rpm. I found it to be very easy to control, and keeping on target was quite easy. A negative would have to be the flash hider- it was opened at the bottom, I immediately went to bipod supported prone position and in that sandy environment it raised a cloud of dust- however, HK has corrected that situation. Shoulder fire was relatively easy to accomplish and the ambush busting “Hip fire” was easy to control as well. (God save me if Peter K reads this and thinks I advocate “Hip Fire”).

Please read through the accompanying picture captions for a better view of the HK MG43 machine gun. I am certain that we will be hearing a lot more about this new offering.- Dan

HK MG43 Machine Gun Specifications

Caliber: 5.56 x 45mm NATO
Operating System: Gas Operated
Bolt system: Positively locked, rotary two lug bolt head
Mode of fire: Sustained fire
Rate of fire: 750 Rds/ minute
Overall Length: 1050 mm, 810 mm with buttstock closed
Width: 90 mm
Height- bipod folded:….250 mm
Barrel Length: 480 mm
Weight: 6.4 kg
Bipod Weight: 0.43 kg
Barrel Weight: 1.72 kg
Standard Sights: Adjustable rear sight with range marks from 100 to 1000 meters in 100 meter increments.
Optical Sights: Picatinny rails on the top cover allow for the installation of various day and night sights.

There is no other weapon so closely connected with the Navy SEALs of the Vietnam era than the Stoner light machine gun. For the operators in the Teams, the weapon was either lauded or vilified, loved or hated, with very little middle ground.

In spite of appearances, the Stoner 63 system and its variants were not first taken into combat by the men of the Navy SEALs. Instead, the U.S. Marine Corps had combat tested the Stoner as early as 1966. The USMC tested the Stoner, had it modified, liked it, and were promptly told they couldn’t have them.

As has been mentioned, the Stoner 63 was unique in the field of military weapons. A single receiver could be used to assemble any of a variety of weapons, from short carbine to a fixed machine gun. When set up as a carbine or rifle, the gas system of the Stoner is above the barrel and the weapon fires from closed-bolt. Set up as a belt or magazine fed machine gun, the gas system of the Stoner can be seen below the barrel and the weapon fires from open bolt. This arrangement allows the Stoner to fire most accurately (closed bolt) as a shoulder weapon while the open-bolt system allows air to circulate better and prevents cook-offs in a support-fire automatic weapon.

Early in 1967, the SEALs first became interested in the Stoner 63, primarily as a belt fed light machine gun. The SEALs were entering a new stage in their direct actions in Vietnam. SEAL Team Two was just starting to deploy platoons for combat in Vietnam at the end of January, 1967. Maximum firepower in a minimum package was a prime concern to the SEALs. On January 17, 1967, the US Navy Test Station ordered eight Stoner 63 light machine guns for testing in combat by the SEALs.

Within a month of the new Stoners being received by the Navy, they were sent out to the SEALs in Vietnam. The limited number of weapons available resulted in only one Stoner being shipped to each deployed platoon. Though the Stoner was known for requiring regular maintenance for consistent functioning, the weapon was well received by the SEALs.

SEAL TEAM ONE – COMMAND AND CONTROL HISTORY – 1967

SPECIAL TOPICS

(b) PERFORMANCE OF WEAPON SYSTEMS

The Stoner system malfunctioned frequently, but the problem has been eliminated to a certain extent by the proper indoctrination of personnel on the gas system of the weapon. The Stoner system performs well when properly cared for and is the most effective automatic weapon for SEAL Team operations. The weapon itself is sufficiently light that the automatic weapons-man can carry a realistic combat load of ammunition and still move with relative ease.

There were a number of difficulties with the new weapon being fielded in the Teams. But in general the Stoner fit the need for a light weapon with high firepower nicely. One of the more unusual problems the operators had with the Stoner was a certain lack of ammunition. Though the Stoner fired the same .223 round the SEALs had in abundance for their M16’s, the Stoners required linked ammunition. Though a limited supply of pre-linked ammunition was supplied, packed in 150-round plastic ammunition boxes that could be hung on the Stoner, the majority of the Stoner’s ammunition had to be supplied locally.

The special S-63 link for the Stoner came packaged in a small cardboard drum that held thousands of links. The link was very much a reduced-size version of the M13 link used with the M60 machine gun but was unique to the Stoner weapons system. There were more problems with the Stoner 63 for the SEALs than just policing used links and loading belts. It was very much a case of one service not talking to the other that resulted in the SEALs having many of the same problems with their Stoners as did the Marine Corps when they tested the system.

In spite of the minor difficulties run in to while fielding the new weapon, the Stoner soon earned itself a solid position in the SEALs armory. The Stoner needed more cleaning and closer attention to detail in its maintenance than other weapons did, and there were still bugs that had to be worked out of the system.

The SEALs liked the Stoner, but the weapon still needed a good deal of improvement before being fielded in quantity. When the second Platoon of SEAL Team Two returned from Vietnam after their first deployment, a series of recommendations were listed by the Platoon officers and men. Included in these recommendations was a very specific one directed to the Stoner;

Excerpt from SEAL Team Two, 2nd Platoon’s Vietnam operations, 30 January to 30 May 1967

Weapons and Equipment

8. Use of the Stoner LMG is not recommended until the drum magazine becomes available.

The plastic box used to attach a supply of ammunition was considered just too difficult to use in its available form. Hanging as it did one the side of the LMG, when the box was knocked off by an operator’s knee, the ammunition belt would just trail out of the box into the mud. This was only one of several recommendations taken into account by the Navy when they ordered additional Stoners for the SEAL Teams. On 25 May, 1967, Cadillac Gage received a phone call from the Naval Ordnance Test Station requesting a delivery date for 36 additional Stoners. All of these weapons were to be 63As in the light machine gun configuration and equipped with the 150 round drum magazines.

The Stoner machine gun had become a stock item in the SEAL armory by the middle of 1967. Several hours were dedicated to the weapon, its use, and its maintenance during pre-deployment training for Vietnam. Each deploying SEAL platoon now had at least two Stoners, one for each squad, with more desired. SEALs who demonstrated a penchant for the weapon were usually allowed to carry one. These SEALs were often referred to as Stonermen in later recounting of particular actions. For the weapon itself, SEAL Team One was the primary unit for developmental items and the Stoner was secure on their list for attention;

SEAL TEAM ONE – COMMAND AND CONTROL HISTORIES

1967, Enclosure 3, (j) Research and Development, pg 13-14

.. A listing of special procurement actions completed is summarized below:

(#22) Stoner 63A
(#28) Stoner Drum Magazine
(#29) .223 Linking Machine for Stoner Ammunition

The new drum for the stoner made the weapon considerably more dependable while moving. An ammunition belt was secured in the drum and held underneath the receiver, close to center of balance of the weapon. Early experiments by Cadillac Gage in 1966 had resulted in a small 100 round drum, but this device was quickly dropped as impractical. The first model drums were made of spun aluminum and had a double-pinned bracket that secured them to the bottom of the receiver at the back of the forestock and front of the trigger group.

The double-pinned drums were secure, but very difficult to reload without taking them completely off the weapon. The second model drum was secured by a pin to the rear of the forestock where it was free to pivot. The rear portion of the drum mount had a lug that fit under the magazine catch on the front of the trigger group. This model drum could be unlatched and swung down for reloading without having to completely dismount the drum from the weapon.

The drum was mechanically very simple, not much more than a round container with a removable back. A 150 round belt would be coiled together in a counter-clockwise spiral and inserted into the back of the drum with the bullets forward. The loose end of the belt would be slipped up the guide located on the left side of the drum. The back of the drum would then be secured in place with its twist-latch and the ammunition supply for the Stoner would be ready for use.

A stamped-metal cover was hinged at the outside, top of the feed guide on the left side of the drum. This cover could be folded back, exposing a short length of the belt. A somewhat fragile spring clip was on the side of the drum’s feedway to help keep the loose belt from slipping back into the drum.

Individual SEALs developed their own manner of carrying ammunition for their Stoners. Since the drums were relatively slow to reload during a patrol, the loaded drum would be kept secured for use while moving on patrol. When set up for an ambush, another method would be used to feed the Stoner.

SEALs would often carry their extra supply of ammunition belts slung across their shoulders and crossing the chests and back like bandoleers. Sometimes, an extra t-shirt was worn over the belts, keeping them out of the worst of the dirt and mud and preventing them from shining. On getting into a fixed position, such as an ambush site, the belt in the drum of the Stoner would be taken out of the feed tray and left hanging from the drum.

A loose belt of ammunition from the SEALs “bandoleers” would be piled next to the weapon, possibly on a piece of cloth or gear to keep it out of the mud, and loaded into the weapon. In case the SEAL with the Stoner had to break cover and move out, it was a simple matter to snap the end of the drum’s belt onto whatever belt was left in the feed tray.

Unlatching the magazine release allowed the empty drum to swing down until the back cover was free of the weapon. Turning the cover latch would remove the whole back of the drum. To reload the drum in the field, a SEAL could reach to his bandoleers of belts and break the link connection between any two rounds.

Keeping the loops of belts in 150 round or shorter lengths made the next step in reloading a drum relatively easy. The SEAL would pull out his loose belt of ammunition, wrap it clockwise around his finger, and slip it into the back of the drum. feeding the end of the belt up the feed chute, securing the cover, and snapping the drum back into place underneath the weapon allowed the fresh belt to be loaded into the receiver.

Other SEALs made additional modifications to their weapons to fit them to the individual’s taste. No changes were allowed that could jeopardize the dependability of the weapon, otherwise it was up to the individual SEAL. When the Stoner 63A’s arrived at the two SEAL Teams, they were accompanied by a number of complete systems for the weapons. Though the primary configuration of the Stoner used by the SEALs was as the belt fed light machine gun. At least two SEALs used other configurations.

These SEALs found the carbine configuration of the Stoner to their liking. The only magazines supplied with the Stoner systems held a full 30 rounds of ammunition. This larger magazine capacity was considered a big plus by the SEALs who knew about it. The standard M16 magazine at that time (1967) held 20 rounds. The larger 30 round M16 magazines were available, but were very scarce in the SEAL Teams in 1967 and 1968. The short, handy, Stoner 63A carbine, with it’s folding stock and 30 round magazine was the only other configuration of the Stoner system to see any use by the SEAL Team in Vietnam.

One reason that the Stoner system didn’t see wider use with the SEALs in the carbine or rifle configurations was the limited number of 63A receivers that had been purchased by the Navy. Eventually, all of the available weapons were set up as belt fed light machine guns. But some of the conversion parts were still put to use by the SEALs. At least one Stonerman attached the vinyl-covered tubular steel (referred to as the wire type) folding stock of the carbine configuration to his Stoner machine gun. This made for a very compact package of firepower, even though the folding stock wouldn’t secure properly to the side of the weapon.

In spite of the good reception the Stoner received from the SEALs, there were still a number of problems with the design that had to be worked out. Most of these details developed from the SEALs experience with the weapons. The SEALs also gave their Stoners a lot of hard usage so even with the careful maintenance they received, weaknesses showed up faster with the Teams than they would have with other units.

SEAL TEAM TWO – COMMAND AND CONTROL HISTORIES

1968, Enclosure 1, Special Topics, pg 9

The Stoner LMG has been modified due to suggestions submitted from members of SEAL Team TWO who have used the weapon in combat.

Cadillac Gage was very responsive to the SEAL requirements for modifications to the Stoner 63A. Feedback from the field resulted in a number of minor changes to the weapon. The only difficulty with the company response to the input from the Teams was the gradual changes in the parts to the Stoner system. It soon became hard for anyone not very familiar with the differences between the Stoner 63 and the 63A and the Team’s requested modifications to the 63A to make sure the correct parts went into the correct model guns.

But during the Vietnam era, such problems of commonality of parts were not a difficulty for the SEALs. Operators who preferred the Stoner made sure that their weapons operated correctly, and this testing was conducted constantly during predeployment training. This made sure that any problems were corrected long before any specific Stoner went into combat.

One problem with the Stoner centered on the basic design of the weapon and took a major change to correct it. The ejection port on the Stoner was on the left side of the weapon when set up in the light machine gun configuration. Feeding from either the plastic box hanging from the feed tray or the 150 round drum caused a jam known as “spin-back”.

Sometimes when firing, an ejected cartridge case would strike the box, or more often the drum, and bounce back into the receiver. The empty case would block the bolt going forward and stop the weapon from firing until it was cleared. This problem did not happen constantly, only about one or two percent of the time when the weapon was fired. This spin back problem was serious enough to require correcting.

Moving the ejection port of the Stoner was out of the question as that would require a major change in the receiver and a number of internal parts. Instead, the direction of feeding was changed from the left side of the weapon to the right. The right hand feed involved replacing the feed cover and feed tray but eliminated being able to use the drum magazine. SEALs who found that their individual Stoner either didn’t have spin-back problems, or liked the drum enough to accept the occasional jam, stayed with the left-hand feed. Others used the new right hand feed mechanism and a new method of feeding a belt.

SEAL TEAM ONE – COMMAND AND CONTROL HISTORIES

1969, Enclosure (2) (c) 6, Research and Development

2. SEAL Team ONE is in the process of being supplied with a new type of feed system for the Stoner Weapon, that practically eliminates the danger of shell spinback which was one of the major causes of malfunctions.

c. LINKING MACHINE FOR 5.56MM BALL AMMUNITION – Provides a portable linking machine for 5.56 MM Ball ammunition as used by the Stoner 63A weapon system. One unit is now in SEAL Team [ONE].

Along with the right hand feed mechanism was a new method of loading the Stoner 63A with the 100 round plastic boxes. The hanger was a device that fit underneath the center line of the receiver, in the same position the belt drum was in. A plastic ammunition box could be slipped into the hanger where it would be held securely and the belt fed into the weapon. The box hanger system went through a number of variations with only one design seeing widespread use.

The box hanger that became standard issue was a right hand feed system that held a single 100 round ammunition box horizontally across the underside of the receiver. The belt fed up a covered tray and into the feed cover. A spring-loaded latch was on the inside of the hanger’s feed tray to keep the belt from slipping back into the ammunition box when the weapon wasn’t firing. This latch helped cut back on the strain on the feed mechanism.

A new style of quick-detachable mount was used to hold the standard box hanger in place underneath the receiver of the weapon. A spring-loaded plunger was squeezed to release the front latch, which fit over the forestock holding pin. The rear of the quick-detach mount had a curved protrusion that fit over the front pin of the trigger group. This box hanger only worked with a right-hand feed top cover and feed tray. But other systems were tried.

Both China Lake and Cadillac Gage made a variety of box hangers and drums to try and come up with the best ammunition holding system for the Stoner. Some left-hand feed box hangers were made, but these had the same spin-back problems as the drum. A 250-round belt drum was made in limited numbers at China Lake for testing by the SEALs. But the Stonermen who tried the 250-round drum found it was too large and unbalanced the weapon, making it clumsy to handle.

Other box hangers were tried that held 150 round plastic ammunition boxes or secured the ammunition belt under a long cover, hinged at the bottom. None of these systems found the acceptance of the right-hand feed, 100 round belt box hanger.

But with the belt box hanger came another new problem with loading the Stoner 63A. The cocking lever for the machine gun versions of the Stoner 63A was still in the same location as the lever for the earlier 63 model. The cocking lever had been made longer on the 63A, and was more secure to use. But the box hanger and the right hand feed interfered with the operator easily reaching the cocking handle to charge the weapon. The feed tray of the box hanger would block much of the cocking lever so that the operator could only reach the lever with one or two fingers.

To ease the cocking lever problem, a solution was taken from the carbine and rifle configurations of the Stoner 63A. The forestock for the Stoner 63A machine gun was modified with a wide, six-inch long slot cut in the bottom center of the handguard. The protruding rod cocking lever of the carbine and rifle versions was modified by removing the center plunger and installed under the barrel of the machine gun, fitting through the slot in the bottom of the handguard.

Now a Stoner gunner could use either hand to pull back the cocking rod, easily charging the machine gun with whatever feeding system the weapon might be mounted with. Some operators found the protruding cocking rod to be a little short for their comfort. A piece of tubing forced over the rod of the cocking piece would extend it several inches and satisfy the operators who thought it too small.

The size and weight of a weapon was always a consideration in the Teams. Even with its light weight, the SEALs wanted the Stoner to be made even more compact if possible. Using the carbine configuration barrel as a starting point, Cadillac Gage designed a short, heavy machine gun barrel for the SEALs in 1968.

This short barrel was heavier and larger in diameter than the carbine barrel, but was the same overall length. To cut down on the weight of the short machine gun barrel, the outside was fluted with six deep flutes cut lengthwise into the steel. The flutes removed some weight and increased the surface area of the barrel, allowing it to radiate heat better and cool quicker.

Referring to the new barrel as their “commando” model, Cadillac Gage began supplying the new part to the SEAls in 1968. The short barrel also had a gas port selector underneath the front sight, but this selector only had two settings. The commando barrel could be slipped onto any SEAL Stoner 63A, removing 6.25 inches of length and about 1.56 pounds of weight.

A short commando barrel, right hand feed top cover, and 150-round drum, assembles a Stoner 63A into what is considered the “classic” SEAL Stoner configuration. Most of the 63As in SEAL hands were modified with the new cocking system and the new right-hand feed mechanisms. The short commando barrel had some difficulties in operating the Stoner in certain environments. With the very short section of barrel, actually just the flash hider, in front of the gas port (underneath the front sight) there is very little residual gas pressure to operate the action of a Stoner fitted with the short barrel. The longer standard barrel maintained a higher gas pressure for a longer time when the weapon was fired. This allowed for a greater level of energy to be available to operate a dirty or sluggish action.

But a number of SEALs swore by the new short barrels and made sure that their Stoners remained as clean and well lubricated as possible. The advantage of the short commando barrel was that it made a compact weapon even smaller and easier to handle in the close brush and jungle. Some SEALs made the Stoner an even more compact weapon for close-in use by removing the buttstock completely and trying a piece of line onto the weapon to act as a sling.

The short commando barrel, right hand feed, and 100 round box hanger completed the final version of the SEAL Stoner. This weapon resulted from the input of the SEALs having used the Stoner in combat for almost two full years. In this final form, the Stoner received a nomenclature assignment by the Navy as the Mark 23 Mod 0. The original request for the nomenclature was submitted on 14 March 1969, Mark number assigned on 31 October 1969, and the final approval made on 4 December 1969. The description of the weapon on the assignment request was;

Gun, Machine, 5.56 Millimeter, Mark 23 Mod 0 …is a gas operated 5.56MM automatic weapon using disintegrating metallic belts, belt fed, fires from the open bolt position, has a quick change barrel, with right hand twist rifling (6 grooves) one turn in 12 inches, fires 700 to 1000 rounds per minute, with a muzzle velocity of 3256 feet per second. Giving a maximum range of 2895 yards (2653 meters), the maximum effective range is 1203 yards (1100 meters). The overall length is 40.25 inches. The gun empty weighs 11.68 pounds. Manufactured by Cadillac Gage Company, Roseville, Michigan. Company designation is 5.56M light machine gun, belt fed, Stoner 63A

The nomenclature assignment fit both the long and short barreled Stoner, with either the right or left hand feed. All Navy purchases of the Mark 23 Mod 0 were of the short-barreled, right hand feed versions with the 100 round box hanger. The Mark 23 was offered by Cadillac Gage to other military customers as the “Commando machine gun.”

The correct nomenclature of the final configuration of the SEAL Stoner becomes difficult at this point. The Mark 23 Mod 0 Stoner was referred to as the Stoner 63A in most Cadillac Gage literature and this was the designation used by SEAL Team Two.

Receiver markings on the Stoner series had not significantly changed during the entire production run except for the address of the company. All Cadillac Gage Stoners were marked STONER 63 .223 CAL. just in front of the serial number. All of the modifications requested by the SEALs and incorporated as a whole in the Mark 23 resulted in significant changes in the weapon. Both SEAL Team Two and Navy documentation refer to the Mark 23 as being known commercially as the Stoner 63A1.

NWM of Holland had licensed production of the Stoner weapons system for sale in Europe. Only a handful of the Dutch weapons were produced, reportedly on about 60 US made receivers. These weapons were advertised in a September 1969 booklet produced by NWM and titled the Stoner 63A1 Weapons Modifications. The machine gun configuration illustrated in the booklet, identified as the XM207, was identical to the Mark 23 except for an NWM designed bipod and mount and a long barrel.

The most numerous Stoners in SEAL hands were the Mark 23/63A1 weapons purchased by the Navy in 1969 and 1970.

SEAL TEAM TWO – COMMAND AND CONTROL HISTORIES

1969, Enclosure 1, VI NEW EQUIPMENT, pg 14

4. (U) During the year, the Team received twelve new Stoner 63A1 light machine guns which, although they are only half the operational quota requested, will help provide each platoon with greater firepower in the field.

SEAL TEAM TWO – COMMAND AND CONTROL HISTORIES

1970, Enclosure 1, VI. NEW EQUIPMENT, pg 12

3. (U) Twelve new Stoner 63A1 light machine guns were received. Each deployed platoon now has two of these weapons per squad.

Estimates according to available documents puts the number of Stoners purchased outright by the Navy for the SEALs at 8 Stoner 63s, 36 Stoner 63A’s, and 48 Stoner 63A1’s (as Mk 23’s). Additional Stoner receivers and systems may have been transferred into the Teams from the stocks of Marine weapons that had been turned in to storage.

With the final acceptance of the Mark 23 machine gun, no further purchases were made of parts for the Stoner 63’s that were in inventory or accessories that would fit the earlier weapons. This means that drums gradually became harder to find for those SEALs who preferred that method of loading. Though the drums were simple and had few parts, the method of securing the rear cover with a twist latch was subject to wear. This resulted in an increasing number of drums being sealed with tape prior to going out on an operation. This made reloading the drums very difficult in the field.

As a field-expedient solution, a number of SEALs modified a mount for the Stoner that would accept the ammunition drum from the Soviet RPD machine gun. The Soviet RPD used a stamped steel drum to contain a 100-round non-disintegrating metal belt of 7.62x39mm ammunition. The drums were commonly found in munitions caches and were available to the SEALs in some numbers.

Each RPD drum would hold a 150-round belt of Stoner ammunition easily, and feed it smoothly into the weapon. The quick-detachable mount portion of an ammunition box hanger could be removed by simply cutting away two rivets. A sheet metal extension would be locally fabricated and secured to the mount with two screws. The addition of a twist latch, such as used on a screen window, completed the mount. The RPD drum mount would fit underneath a Stoner and could be set up to feed into either a right or left-hand feed weapon. In addition, an empty RPD drum was easily and quickly exchanged for a loaded one to reload the weapon.

Throughout the Vietnam War, the Stoners were demonstrated to be a useful addition to the SEALs arsenal. But this didn’t come without a cost. Technical training on the Stoner weapons system was increased to help minimize problems with the weapon.

SEAL TEAM TWO – COMMAND AND CONTROL HISTORIES

1969, Enclosure (1) V. PREDEPLOYMENT TRAINING

Some members of deploying platoons…….received special training in the maintenance and use of the Stoner 63A1 light machine gun and the M16A1 rifle. The machine gun instruction was administered by the manufacturer of the weapon, Cadillac Gage Company, Detroit, Michigan

Any new weapons system has to go through a development process to locate and eliminate errors in the design. Sometimes these errors were located with little more than some difficult incidents for the operator.

The quick disconnect barrel of the Stoner was held in place with a push-button latch just in front of the feed cover. With the bolt cocked, the only thing holding the barrel in place was the barrel latch. If the latch had been depressed accidentally, such as while moving through brush on a patrol, as soon as the trigger was pulled, in forward moving bolt had as good a chance of pushing the barrel off of the weapon as it did of firing the cartridge it had stripped from the belt.

In spite of the general opinion the SEALs had about the Stoner, there had been some serious incidents with the weapon. One incident in particular almost resulted in the Navy dropping the weapon entirely. To field-strip the Stoner for cleaning, one step in the procedure is to remove a takedown pin found just above and behind the pistol grip, With the takedown pin withdrawn, the receiver can pivot up and away from the stock and trigger group. This allows the bolt and internal mechanism of the Stoner to be withdrawn.

With the Stoner machine gun operating from an open bolt and the sear which holds the bolt in the cocked position part of the trigger group, separating these parts with the bolt cocked will release it to drive forward. If there is a round in the feed tray, the weapon will fire. If there is a belt in the feed tray, the weapon will fire uncontrollably until either the belt runs out, or the bolt flies out of the back of the partially opened weapon. Something very close to this situation happened to a squad of SEALs from SEAL Team One while inserting on an operation.

Mike Platoon of SEAL Team One was operating in the Kien Hoa province of Vietnam, having moved down into the Mekong Delta area from the Rung Sat Special Zone just a short time earlier. On 29 April, 1968, the platoon was moving in for an insertion from a Mark 4 landing craft. The trip to the insertion point was an uneventful one up to a point. The SEALs were relaxing aboard the boat as was normal prior to an operation. One SEAL, Walter Pope, was armed with a Stoner 63A fitted with a 150 round drum. The Stoner was up, leaning against the side of the armored landing craft as the unit moved along the waterway.

It was never determined exactly what happened next, but the sudden results were that Pope’s Stoner fell over on its side as it began firing wildly. According to witnesses, Pope had not been touching the weapon when the incident began, but suddenly the Stoner was firing uncontrollably.

Frank Toms, reclining nearby, was half-asleep when the accident happened. He was suddenly awakened when he was struck with an estimated 6 to 10 bullets from the runaway Stoner. Walter Pope dove onto the firing Stoner and pulled it into himself to stop the firing and protect his teammates in the boat. Pope took an estimated 40 rounds from the Stoner but prevented any one else from being struck with the ricocheting rounds bouncing around inside the armored boat.

First Class Boatswain’s Mate Walter Pope was killed instantly, but saved his fellow SEALs in the boat. Frank Toms recovered from his wounds. The intense investigation that followed could only come up with the most probable reason the accident occurred. The take down pin on the trigger group of the Stoner at that time was retained by it’s own friction and a small spring detent in the pin itself. It is thought that the vibration from the boat’s engines and pitching of the craft in the water worked the takedown pin free of Pope’s Stoner.

Sitting as it was, muzzle up, the force of gravity as well as the spring tension inside the cocked weapon would have combined to separate the two parts of the receiver, releasing the bolt to drive forward. In this situation, the weapon would have continued firing until it had jammed or run out of ammunition.

As far as Frank Toms is concerned, Pope’s actions that day saved his Teammates and is deserving of the highest award that can be given. The SEALs were in immediate contact with Cadillac Gage about the incident, how it happened, and how to prevent it from ever happening again.

The pivot pin that held the feed cover to the receiver of the Stoner was secured in a different manner than the detent-held takedown pin. The pivot pin is made of two parts that screw together securely, and are further held together by a spring detent inside the body of the pin. It takes the point of a bullet to release the detent and then the two parts have to be unscrewed before the pin can be removed.

This pin was immediately supplied by Cadillac Gage to the Teams in sufficient quantities to replace all of the earlier pins in service. The field stripping procedure on the Stoners with the new pins took a little longer, but the accidental discharge of a weapon due to the receivers separating didn’t happen again.

The Stoner was not the only light machine gun used by the SEALs in Vietnam, But it was one of the most unique. All production of the Stoner ceased by 1971 and Cadillac Gage closed the records on the weapon system in 1973. The Stoner remained in the SEAL inventory until the early 1980’s. By 1983, the last few Stoners remaining in SEAL hands were removed from active duty due to a lack of parts and support to maintain the weapons in operating condition.

On March 30, 1964, Cadillac Gage received order SS-22 for 60 rifles and 20 complete systems from ARPA, The large order was for weapons to be tested by the US Marine Corps. The Marines had been suitably impressed with the Stoner system and ARPA had agreed with their request to field test the new weapon.

Marine enthusiasm for the Stoner was well received and they took in some of the earliest weapons made. Stoner 63’s, serial numbers 00004 and 00005 are still maintained in the Marine Corps Museum’s small arms collection. Springfield Armory also ordered two fixed Stoner 63s during the Spring of 1964 for test purposes.

In May the Aberdeen Proving Grounds report on the Stoner was made to the Army. In July, the Office of the Chief of Research and Development made his report on the Stoner to ARPA. Neither of these reports listed the weapon in glowing terms. This situation is hardly surprising given that the Army had just recently been forced to accept a number of AR-15 rifles.

The leadership at Cadillac Gage still thought the future of the Stoner 63 looked promising. The manufacture of the weapon centered around sheet metal stamping, forming, and precision welding. The California Cadillac Gage facilities were inadequate to the task of mass producing the new weapon but the company also had a manufacturing facility in Detroit where the mechanical support for such manufacture was easily available. Detroit was the center of the automobile industry and the precision forming and welding of sheet metal was a common practice for such manufacture.

In September, 1964, after some 234 Stoner 63s had been produced and serial numbered, Cadillac Gage moved the production of the weapon to their facilities in Michigan. The Arms Development and Engineering staff, Eugene Stoner among them, moved to the newly set up Weapons Manufacturing Facilities in Roseville, Michigan, just north of Detroit. At this time, the wooden stocks and pistol grips on the Stoner 63 were changed. Grips and stocks were now made of polycarbonate plastic, though the forestock for the machine gun configuration remained black-painted wood.

General Wallace Green, the Commandant of the Marine Corps, had been impressed with the idea of the Stoner family of weapons. This may have come about in no small part due to Cadillac Gage hiring a newly retired Marine Colonel who, during the end part of his military career, spoke to General Green convincingly on the advantages such a system offered to the Corps. Colt at the time, was offering what they called a family of weapons based on the AR-15. But the Colt weapon system, the CAR-15, was made up of specific firearms which could not be interchanged easily. This did not meet some of the advantages of the Stoner 63.

The situation did start to look very good for the future of the Stoner 63 system in 1965. On 23 April 1965, the Army Weapons Command put in an order for 861 Stoner weapons in various configurations for testing as part of the new Small-Arms Weapons Systems (SAWS) program. Within just a few days of this purchase order being issued, the Marine Corps Landing Force Development center (MCLFDC) test report was delivered to Marine Corps Headquarters.

The MCLFDC report recommended the Stoner 63 for further, more advanced, field testing. This report helped fuel the enthusiasm for the Stoner 63 among the Corps Command and Marine Corps Commandant General Wallace Greene in particular. This situation was not well received by the Army Weapons Command who strongly disliked the new AR-15 rifle over the M14 rifle. For the Army, it was now looking like the Marine Corps was going to push for another, completely different, .223 caliber weapon that also could compete with the still new M60 machine gun.

On 20 December, 1965, the Marine Corps put in an order for 1,080 Stoner rifles as well as the parts necessary to assemble other configurations of the weapon. Extensive testing of the Stoner system by the Marine Corps did indicate some weaknesses in the system that needed correction. In the first several months of 1966, these weaknesses were identified and brought to the attention of Cadillac Gage.

While the modification problem was being addressed, the Marine Corps continued their testing of the Stoner 63 system. results from the field were varied, but in general, the weapon system was well liked by many of the men employed in testing it. Substantial tactical and logistical advantages were found in using the system by the evaluation groups. Testers included one rifle company, a platoon of the division reconnaissance battalion, and a platoon of the force reconnaissance company.

An almost immediate change to the fielding of the Stoner weapons system during evaluations was the dropping of the automatic rifle configuration. It was found that the automatic rifle was the least dependable of all of the Stoner 63 configurations. This was due to the top-loading magazine feed used in the automatic rifle. It was found during Marine testing that every time the automatic rifle was loaded, any sand, dirt, or foreign material in the magazine was poured directly into the receiver. With the open bolt of the automatic rifle configuration, this material jammed the action causing an unacceptable number of stoppages.

The remainder of the Stoner 63 weapons system was evaluated by the Marine Corps during March, April, and May, 1967. A comparison testing of the new M16E1 was conducted by the same test groups during June and July of that same year. Test results were tabulated and the report made at the end of August that same year.

Testing showed the Stoner rifle had the advantages of weight, accuracy, improved ammunition, and compatibility with other weapons (the balance of the 63 system), when compared to the standard M14 rifle. The Stoner rifle was found to have a lower reliability than the M14, but this problem was considered correctable with modifications. The difference in reliability between the Stoner 63 and the M14 was not considered significant when considering the overall advantages of the entire system. When compared to the M16E1, the Stoner 63 Rifle was found to be more accurate, more reliable, and had a family of weapons that it was compatible with.

The Stoner light and medium machine gun configurations also received high recommendations by the majority of Marine testers. The Stoner light machine gun was considered a suitable replacement for the automatic rifle configuration in the Marine rifle squad. The LMG and MMG were found to be highly reliable when compared to any other machine gun in the Marine testing environment.

The Marine testing was extensive. Boot Camp trainees were issued with the Stoner and completed their training cycle with it, in the process scoring higher during weapons qualifications than any comparable Marine unit. Stoners were taken into limited combat in Vietnam, where the design was proven to be accurate and reliable in the jungle environment.

The results of the first major Marine Corps evaluation of the Stoner 63 weapons system were very positive. In the words of the evaluation committee;

3. The basic conclusions of the evaluation are that the Stoner family of weapons provides substantial tactical and logistics advantages. There are some relatively minor modifications required prior to acceptance but none of these appears to create any problem. The system received a high degree of acceptance from personnel involved.

4. The Stoner Weapons System is strongly recommended for adoption.

Some of the difficulties with the Stoner 63 had been addressed by Cadillac Gage prior to the evaluations being run by the Marine Corps. The order for evaluation weapons put forward by the Marine Corps in December 1965, had been filled with the available Stoner 63s. The redesign of the Stoner 63 to the Stoner Model 63A was completed in March 1966. Changes from the Stoner 63 to the 63A configuration include;

a. Larger gas port opening b. Chromium plated chamber c. Stronger and better fitting dust covers d. A relieved breech block cam pin e. A gas nitrided bore f. Separate safety in front of trigger guard g. Feed tray machined casting instead of stamped metal h. Three position gas port valve i. Redesigned stock and forearm of polycarbonate material j. Three piece cleaning rod fitted inside of forearm k. ENDURION metal finish on all exposed surfaces l. Bipod locks onto weapon or locks open for stowage m. Right side belt feed mechanism available, exchanges w/left side feed n. Over-the-shoulder assault sling available o. Upper sling swivel attached to front of barrel handle

The removable trigger guard of the Stoner 63, intended for using the weapon when wearing gloves or mittens and easily lost during testing, was replaced with a permanently attached trigger guard. The size of the plastic ammunition box that could be hung onto the side of the light machine gun was reduced from 150 round to 100 rounds. It was found that the larger box was easily struck by the users leg when patrolling and could be knocked off the weapon.

Other changes to the system included replacing the folding stock of the carbine with a wire folding stock that had considerably fewer parts. The cocking handle of the Stoner 63 was the same for all of the weapons in the system. A perforated length of handle with an outward curved end extended along the side of the handguard, right over the gas tube. On the rifle/carbine versions of the Stoner 63, this handle was on the upper left side of the weapon, above the forestock. On the machine gun versions, the cocking handle was at the lower right side of the weapon, just behind the forestock.

For the rifle and carbine versions of the Stoner 63A, the cocking handle had been completely changed from the original. A small lug had been welded onto the operating rod, several inches behind the piston head. The new cocking handle was located on top of the receiver, over the barrel and handguard, where it could be reached by the operator with either hand easily. The new cocking lever rode along a slot cut into the receiver, just below the gas tube, and engaged the lug welded onto the operating rod. A plunger in the center of the operating handle could be pushed down by the operator and used to push the bolt forward to assist it to close.

For the machine gun versions of the Stoner 63A, the cocking lever engaged the new lug on the bottom of the operating rod, but was otherwise in the same place as in the earlier system. The machine gun cocking rod had been made longer so that it could be more easily reached.

The feed cover of the machine gun had been improved in both strength, manufacture, and function. The cap carrier had been redesigned to include a spring plunger mechanism. In the Stoner 63A, the feed cover could be closed with the bolt in any position while in the Stoner 63 the feed cover could only be closed with the bolt in the cocked position to insure no damage to the weapon.

Another change to the feed system of the Stoner 63A was the development of a drum carrier for the ammunition belt. The final drum design would hold a 150 round ammunition belt securely to the bottom of the weapon and feed the belt in smoothly while firing. The drum was made of spun aluminum to keep weight to a minimum and was securely attached to the receiver of the 63A.

To help keep the system from being jammed by excess dirt, spring loaded covers were placed over both the ejection port of the receiver and the link ejection port on the feed cover. The ejection port cover on the receiver would spring open and remain that way as soon as the bolt carrier moved. The cover over the link ejection port only opened when a link was being ejected and otherwise remained closed.

The gas tube of the 63A was made from 17-4 PH stainless steel to minimize corrosion and giving the new tube a silver outside finish. The inside of the gas tube of the 63A was remachined to prevent carbon build up from jamming the gas piston. This allowed the 63A to fire for longer periods of time between cleanings of the gas system. From roughly serial number 2,000, all Stoners produced by Cadillac Gage were built as 63A’s. No changes were incorporated in the markings Cadillac Gage stamped into the receivers of their Stoners and all weapons remained marked “Stoner 63”.

The large number of improvements in the Stoner 63A system made the weapon of even greater interest to the Marine Corps. On 3 October, 1966, Cadillac Gage received an order from the Marine Corps to modify 286 weapons to the new 63A configuration. The new weapons were scheduled for extensive testing under combat conditions in Vietnam. This combat test series was to be completed by May 31, 1967.

On March 3, 1967, a further order was received from the Marine Corps, this one for an additional 8 weapons to be converted to the 63A model. These additional weapons were intended for further testing under controlled conditions to confirm the field trial results. The tests did confirm what had been determined by most of the Marine users. The Stoner 63A was considered suitable for Marine Corps use without further testing.

Cadillac Gage received a further order from the Marine Corps on 19 April, 1967, for ammunition linking systems and spare parts for the overseas support of the 286 63A systems in Marine Corps hands. But shortly after this order was received, the Army Weapons Command declared the Stoner 63 and 63A to not be acceptable for issue at the time.

Without much fanfare, all of the Stoners in Marine hands were to be turned in. The Army was still interested in the Stoner 63A as a light machine gun, but only as a low-priority project. Army tests of the Stoner to approve the system for procurement were considered extremely biased. But for whatever reason, the question of the Stoner in Marine hands was over by the middle of 1967.