At the end of the 1960s, tensions between the Catholic and Protestant communities in the British province of Northern Ireland, which had been simmering for some time, erupted into violence. Among other things, this faced the police and the army with major crowd control problems, particularly since protesting crowds frequently contained (and sometimes still do contain) members who attacked the police with bricks, fire bombs, blast bombs and even firearms. It was important to find ways of combating such attacks without using lethal ammunition, which would cause too many deaths and thus inflame the situation even more. The police and the army therefore adopted various tactics and less-lethal weapons in order to break up violent demonstrations and target specific trouble-makers within them. While CS gas and water cannon have been used against crowds in general (and water cannon still are), the need to target specific individuals within the crowd led to the adoption of 37mm calibre riot control guns firing baton rounds (nowadays known as impact rounds).

The problem facing the designers has been how to make a projectile which will hit with disabling impact out to beyond the crowd’s object-throwing range, without being lethal at short range. They have achieved this by adopting big, heavy, low-velocity baton projectiles. An advantage over smaller-calibre projectiles is that they are big enough to minimize the chance of entering an eye socket and penetrating the brain. The normal operating range for a baton round is 20-40 meters, but they may be fired at much shorter ranges in an emergency. These batons are designed to be fired at the abdomen and legs (the latter particularly at short range), as there is a risk of serious and potentially fatal injury if they hit the chest or, especially, the head. Over the period 1970-2005, some 125,000 baton rounds have been fired in Northern Ireland. These have resulted in 17 deaths, the last being in 1989. This works out at an average of ten rounds per day and one death every two years, or a death rate of 0.0136%.

Until recently, these weapons were not used in other parts of the UK, but in 2001 (in conjunction with the introduction of the L104A1 gun and L21A1 round) it was decided to make them available to police forces outside Northern Ireland. In these areas they have not so far been used in riot situations, but as an alternative to lethal weapons against individuals who are posing a threat to others. Between 2002 and 2004, some 50 baton rounds were fired in England and Wales in 37 separate incidents. The ranges varied between 1 meter and 25 meters, and 94% hit their target (compared with 67% for lethal firearms). No deaths or serious injuries resulted.

The baton rounds have evolved over the last 35 years and this article describes the major types used.

“Rubber Bullet”

This was the original baton round used from the late 1960s until about 1975. It uses the same case as the standard 1.5 inch/38mm flare gun cartridge, but loaded with a long, pointed, rubber baton. The case is 122mm long with a rim diameter of 43mm and an outside body diameter of 39.4mm near the rim, stepping down to 38.6mm at a height of 22mm above the rim. The baton is 149mm long and weighs 174g. The gun was smoothbored.

L5 Plastic Baton Round

This plastic baton round, or PBR, was introduced in 1973 and replaced the rubber bullet within two years. It was initially known as the “1.5 inch” round. This used a similar 37×122 cartridge case, except that the outside diameter remains at 39.4mm throughout. The obvious difference is that the baton is flat-nosed and made from polyurethane polymer. The L5 remained in service for a long time and went through several marks, the last being the L5A7. The baton is 98mm long, weighs 131g and is fired at 63 m/s.

L21A1 Plastic Baton Round

This PBR was a new departure, introduced in 2001 in conjunction with a new riot control gun, the L104A1 made by Heckler & Koch. This gun has a rifled barrel, which in conjunction with the X1 18E3 optical sight and more consistent ammunition performance provides far greater accuracy. (When fired from smoothbores, the earlier rounds tend to tumble in the air). The cartridge case is slightly shorter at 103mm, and the baton has more rounded edges to achieve a longer effective range. However, the Defence Scientific Advisory Council concluded as a result of tests that the L21A1, although delivering similar impact energies to the L5A7, could be slightly more dangerous if it struck the head. The baton weighs 98g and is fired at 72 m/s.

AEP L60A1 Impact Round

This was introduced in June 2005 to replace the L21A1. It was developed to reduce the risk of inflicting death or serious injury from a head strike, and achieves this by incorporating a hollow nose. On impact with soft tissue this remains intact, but on striking a hard target like the head or breast-bone, it deforms to reduce the peak impact by between one third and a half. This round is known as the AEP, which stands for Attenuated Energy Projectile. The cartridge case, projectile weight and muzzle velocity remain the same as the L21A1, but the case is painted light grey instead of the black of earlier baton rounds. The AEP is claimed to exceed 95% accuracy against a 400mm x 600mm target at 50 meters.

Ammunition Manufacturers

The British government does not release information about the manufacturers of baton rounds, probably because they have always been (and remain) controversial in Northern Ireland, due to the deaths and serious injuries which their use has occasionally caused. However, it is known that substantial orders for baton rounds have been placed in Germany. In the 2004/5 financial year, a German company or companies supplied 34,272 L60A1; 267,276 L21A1; and (surprisingly) 50,000 L5A7 rounds. The cost of the baton round is approximately £7 each.

ARWEN Ammunition

The ARWEN (Anti-Riot Weapon ENfield) was developed by Royal Ordnance UK and introduced in 1977. However, the rights to manufacture the guns and ammunition were purchased from Royal Ordnance in 2001 by its Canadian distributor, Police Ordnance Company Inc., which continues to offer them to the law enforcement market. These guns were not selected for use in the UK. Unlike the riot guns used by British police, which are single-shot, the ARWEN 37 family all have a rotary magazine containing five shots, which can be fired in four seconds.

This round is really an “odd one out” as it is incompatible with any other 37mm riot control ammunition, with the exception of a similar range made by Sage Control Ordnance of the USA. It uses a rebated-rim case which is 112mm long. The outside diameter of the case is 39.7mm but the rim measures only 32.2mm. The single projectiles all have a characteristic “tadpole” shape, with the 37mm diameter front section just 50mm long; followed by rear section of similar length which tapers from about 24mm to 20mm. The standard AR-1 baton round projectiles weigh 80g and are fired at 74m/s; they are claimed to have an effective range of 20-100m. Various different loadings are available including a reduced-energy AR-1RE (50 m/s: effective range 1-30m); and a number of combined (chemical + impact) rounds including ones firing four cylindrical sub-projectiles.

Other 37mm/38mm and 40mm Riot Control Ammunition

There is much confusion over the calibres and calibre designations of riot control rounds. Calibres of 37mm, 38mm and 38.1mm are mentioned in manufacturers’ data. In fact, 38.1mm is a straight conversion from the original 1.5 inches. In British use, these have been renamed 37mm because 36-37mm is the actual diameter of the baton. Actual measurements from manufacturers in different countries do vary, but the nominal designation does not help to determine this. Some guns are made to deliberately “sloppy” tolerances so they can fire any 37/38mm ammunition (except for the ARWEN rounds), but with obvious implications for their performance and accuracy.

Armies tend to prefer 40mm rounds which can be fired from their standard grenade launchers, and a range of these has been developed. One maker (Condor of Brazil) offers multi-calibre rounds which can be fired in 37/38mm or 40mm guns. Some 40mm riot-control rounds are extra-long (228mm rather than 122mm) and cannot be fired from all grenade launchers, as there isn’t enough clearance for them to be inserted.

Riot control ammunition – whether 37mm or 40mm – can of course be loaded with projectiles other than plastic batons. Other impact rounds include wooden batons, foam batons, multiple batons, bean bags and rubber balls of various sizes. The US Army uses the M1029 40mm Crowd Dispersal Round, which is loaded with forty-eight rubber balls, each .48 of an inch in diameter. However, like the chemical projectiles (containing various types of tear gas or pepper), these are “area weapons” intended for general crowd dispersal rather than targeting particular individuals. There are also dual-purpose (impact + chemical) rounds intended for use against individuals.

There will always be a need to temporarily disable specific rioters, or anyone posing a danger to others, in situations where lethal force is not appropriate. The latest generation of ammunition is better than ever in terms of both precision targeting, and reducing the risk of death or serious injury.

(I am indebted to Colin Burrows, the Director of Critical Intervention Consultancy Services, and Loui Burke, the Managing Director of Primetake Limited, for providing information used in this article, but any errors are entirely my responsibility.)

The author is Co-editor of Jane’s Ammunition Handbook.

By Jim Schatz

Leaner and Meaner

While there are exceptions of course, guns and ammunition used by American military and law enforcement personnel have generally been getting smaller and lighter rather than larger and heavier during the course of the 20th century. The U.S. M4 Carbine, a lighter smaller variant of the M16A2, is now in service with many conventional military units. Compact pistols are more and more often procured for standard police uniformed issue rather than available full size handguns. The standard U.S. military service rifle cartridge has shrunk from the WWI era .30 caliber cartridge (30-06 Springfield), to the 7.62X51mm NATO (.308 Winchester) round in the early 1950’s to the current 5.56X45mm NATO cartridge commercially known as the .223 Remington. HK now offers the small 4.5 pound UMP45 submachine gun that fires the big, powerful .45 ACP slugs yet the weapon is less than half the weight of most other .45 caliber submachine guns. Even the “Ma Deuce” M2 .50 caliber heavy machine gun exists today in a lightweight high cyclic rate of fire variant. The advent of advanced lightweight materials, stronger steels and alloy metals for barrel and bolt construction, and vastly improved ammunition and bullet technology have increased the lethality and performance of today’s modern military and law enforcement firearms while at the same time lightening and lessening the load of the user.

New Start, new concept

Heckler & Koch has been working behind the scenes in their “skunk works” at their Oberndorf Germany facility on a new small Personal Defense Weapon simply called the PDW. Though primarily designed to meet current and future U.S. and European requirements for a military Personal Defense Weapon the obvious usefulness of such a weapon outside of the military becomes immediately apparent to law enforcement and special operations personnel.

To describe the new HK PDW as revolutionary as some may be tempted to do would be stretching things a bit. As a “bullet launcher” the PDW still kills by kinetic energy as small arms have been doing for centuries. It is however safe to classify this new weapon and ammunition system as a substantial development in this relatively new category of Personal Defense Weapons, a category that until recently only included the 5.7mm FN P90.

Most experts categorize a true PDW as a small easily portable weapon about the size of a machine pistol but one that shoots a non-pistol cartridge. Most PDW’s are also intended to be able to be fired using only one hand though with reduced probability of hit. Modern PDW’s are being promoted to replace handguns, pistol-caliber submachine guns and some assault rifles primarily in military support units. These personnel very seldom employ small arms in combat and when they do only for defensive purposes up close. A simple, easily portable weapon that allows for effective target engagement by lessor trained rear echelon combatants is the original role intended for the PDW. Because of the worldwide proliferation of modern hard and soft body armor today’s PDW must also penetrate protective vests and helmets in order to be effective against the aggressor underneath.

The Ammo

The HK PDW is chambered for a new proprietary cartridge developed jointly by HK and Royal Ordnance (RO), HK’s parent company and a division of BAE Systems, formally British Aerospace. RO is also the UK’s premier small arms ammunition manufacturer. The HK PDW fires a small 4.6X30mm high velocity cartridge that looks more like a small rifle cartridge than a pistol round. The overall length of the round is 1.5 inches and contains a 25-grain projectile, which reaches a muzzle velocity of 2,378 feet per second from the PDW’s 7-inch barrel. A copper-plated solid steel projectile develops @ 310 foot pounds of muzzle energy and develops recoil impulse far below that of 9mm handguns. Yet this steel core 4.6X30mm round will defeat threat (former Soviet SPETsNAZ) body armor comprised of 1.6 millimeters of titanium plating backed by 20 layers of Kevlar at ranges beyond 200 meters with sufficient residual energy to inflict lethal wounds after defeating the ballistic protection.

The “family” of 4.6X30mm ammunition currently includes eight various types of rounds many of which are still under final development. This ammo family includes a steel core military penetrator round, two types of extruded solid copper “CQB” cartridges designed specifically for use in close quarters battle were overpenetration is unwanted. One copper CQB round is being produced with a pointed tip and one with a unique “spoon nose” tip to prevent overpenetration in soft tissue or through building materials. There is also a law enforcement hollow point round that will not defeat soft body armor and dummy, blank, tracer and frangible cartridges for the weapon.

In general terms the HK PDW and its 4.6mm round are designed to provide the capabilities of a 5.56mm rifle or carbine out to ranges of just beyond 200 meters yet from a firearm that is similar in size and can actually be carried and fired like a handgun. At 100 meters the 4.6mm projectile fired from the PDW still retains more energy than a 9mm NATO ball round after perforating the threat titanium/Kevlar vest. The round will penetrate two of these former Soviet vests back to back at a range of 50 meters.

The Weapon

The HK PDW is very small indeed and resembles a large handgun. Compared to the HK .45 ACP MK23 Pistol the PDW is slightly larger though the weight of the two weapons when fully loaded (20 rounds in the PDW, 12 rounds in the MK23) is nearly identical at 2.86 pounds. For sake of comparison the PDW is 1/2 inch longer than an HK 9mm MP5K and just over two pounds lighter. With it’s optional 40 round magazine fully loaded the HK PDW weighs in at just 3.39 pounds.

Unlike all submachine guns, small assault rifles and most machine pistols the HK PDW is designed to be fired effectively with one hand at close range targets (< 25 meters). For a proficient shooter it is relatively easy to engage man-size targets using one hand at ranges out as far as 100 meters in the semi-automatic mode of fire. Accuracy is excellent. 3-inch groups at 100 meters and 8 to 12 inch groups at 200 meters from supported position employing the retractable stock for support are well within the capabilities of the HK PDW. The near absence of felt recoil, comparable to that of a lightweight .22 LR rifle, makes the HK PDW extremely controllable in full auto fire, far superior to any pistol-caliber submachine gun, insuring high hit percentages against obscured, multiple or moving targets common on the battlefield.

Specially designed shoulder rigs and thigh holsters offer the user the ability to securely carry the HK PDW on the person for instant availability. From a tactical style thigh rig the PDW can be drawn and fired like a conventional handgun in seconds. A lanyard loop in the leg rig can also be used to automatically deploy the vertical foregrip as the weapon is removed from the holster. A concealed carry shoulder rig has been developed to allow the user to carry the PDW over the uniform for hands free carry while performing other tasks. The design of the shoulder rig also allows the weapon to be presented in seconds and automatically extends the stock as it is deployed from the rig. The lightweight, small size and flat profile of the PDW when worn in the concealed shoulder rig under a light jacket will make it the weapon of choice for personal protection details in the future.

A fold-down vertical foregrip is positioned forward of the trigger guard and below the barrel. This allows the weapon to be fired using one or two hands and in conjunction with a small slide-out buttstock concealed within the polymer receiver of the weapon. The fairly central location of the pistol grip, which houses the flush mounted 20-round magazine, allows for practical use as a one handed gun. Unlike many pistol-caliber machine pistols such as the HK MP5K the new HK PDW offers greater control and probability of hit due to the 4.6mm rounds minimal felt recoil and long eye relief reflex sight.

The HK PDW is gas operated employing a unique clean shooting system similar to that used with great success in the HK G36 weapons system. A multi-lug rotating bolt head that interlocks with the barrel provides for a secure seal of the breech during firing. All operating controls of the PDW are fully ambidextrous to include the magazine and buttstock releases, the M16-like cocking handle and centrally mounted safety/selector lever. Current prototypes of the HK PDW provide both semi-automatic and fully automatic modes of fire at a theoretical rate @ 700 rounds per minute.

The HK Personal Defense Weapon also possesses a combined forward assist/bolt catch and bolt release lever, sling mounting points and an integral Picatinny sight-mounting rail. Back-up emergency iron sights are incorporated into the design as well. The weapon is produced predominately from lightweight polymers with metal used only where absolutely required. The simple design, minimum number of parts and polymer construction translates to very little user maintenance due in great part to its unique short stroke gas operating system. Barrels are removable with a simple wrench and are thus user replaceable. A threaded barrel is available as an option for the attachment of optional flash hiders, sound suppressors or other muzzle mounted accessories.

The Hensoldt PDW Reflex Sight

The sighting system for the PDW, like the weapon and ammunition family are still in the final stages of development. Developed specifically for the Heckler & Koch PDW by Hensoldt, a division of Zeiss, the small PDW Reflex Sight uses a collector to capture ambient light and illuminate a small gold aiming dot. This dot can be seen with both eyes open whether the weapon is fired at arms length like a pistol or when shot from the shoulder using the buttstock for additional support. The sight includes an optional tritium source or battery back up to power the dot during periods of low or no light. A pair of simple recessed Allen head screws allows for internal windage and elevation adjustments of the 7.5 moa dot.

Like everything else about the HK PDW and 4.6mm ammunition, this unique PDW sight is designed to be lightweight, portable and durable under the harshest environmental conditions. For use with the PDW, HK designed their own simple rail grabber sight base that can be used to attach the Hensoldt sight to any Weaver or Picatinny (MIL-STD-1913) accessory rail in under a second and without tools or hardware of any kind. The presence of the Picatinny mounting rail on the top of the PDW will allow a wide range of sights to be attached using currently available rail grabbers.

Operational Uses abound

With a maximum effective range of greater than 200 meters the small size of the weapon, similar to a large handgun, will allow it to be used effectively for VIP protection where the weapon must be concealed yet readily available. Its ability to defeat threat body armor and vehicle windshields and body panels would make it perfect for facilities defense where overpenetration and maximum range of a rifle in urban areas might be of concern. Certainly in a classic role as a PDW for military pilots, drivers, artillery and armor crewman, medics, communication specialists, members of crew served or anti-tank weapons crews, forward observers and behind the front line support personnel the HK PDW will be far better than a handgun from a terminal performance and hit probability standpoint. The 2.86-pound HK PDW promises to be far more portable and manageable than a rifle, carbine or smg, especially in confined spaces like vehicles, aircraft and within mobile communications trailers. The author has worn the PDW in the leg rig while running, climbing and driving. It is a weapon that does indeed “wear” comfortably like a pistol yet hits like a rifle at a distance of more than two football fields.

Current Status

Prototypes of the Heckler & Koch PDW have been undergoing testing for more than four years and to date have seen limited exposure in the United States. At this point the PDW is being shown to select prospective users for design input and comment. HK PDW’s are not yet available for customer demonstrations. Availability of production weapons is not expected before mid-2001. The 4.6mm ammunition is already in limited series production and available from the Royal Ordnance Radway Green factory in England to support the continued development and early user evaluation of the weapon. HK is negotiating with several U.S. ammunition companies to have the ammunition produced in America as well as in the U.K. Projected ammunition unit cost is expected to be very affordable, less than 9mm ball ammunition, and all rounds will be non-toxic to meet growing concerns in this area.

Certainly this new Heckler & Koch Personal Defense Weapon marks a serious attempt to provide the true performance required of a personal weapon and in a small package that can be easily carried and thus always available. If during the remaining testing the weapon and new cartridge perform as expected the HK Personal Defense Weapon could be the future choice for an entire spectrum of users.

About the author: In addition to being a regular contributing writer for this magazine, Jim Schatz is also a full-time employee of Heckler & Koch, Inc. Since 1986 Jim has served with HK in the roles as a training instructor and customer service, sales and product developer for HK’s Federal Operations Department serving all U.S. federal law enforcement and military organizations. The information and opinions provided herein are those of the author and not HK.