Text & Photos by Jeff W. Zimba
From a distance it looks like another tricked-out M4-style black rifle. There is something a little different but it may take a second to put your finger on it unless you are a died-in-the-wool AR-15/M16 fan. While it looks like an M4 on steroids, there is no doubt it is a 7.62x51mm NATO powerhouse.
The original DPMS LR-308 was tested in Small Arms Review (Vol. 8, No. 5, February 2005) and was very well received so the bar was set high for this latest addition to the DPMS Panther Arms .308 line up. Originally tested with a 24-inch, Stainless Steel Heavy Barrel and A2 Mil Spec Stock, this newer AP-4 variant sports a much lighter, and shorter 16-inch barrel that is contoured similar to the original 5.56x45mm M4, and has a 6-position telescoping stock.
The lower receiver and bolt group are the same as the LR-308 with all the changes to the AP4 upgrade being in the upper receiver. The upper receiver is a thick-walled extrusion from 6066-T6 aluminum. It is hard anodized and Teflon coated black to perfectly match the LR-308 lower receiver. The shell deflector and forward assist unit are machined as a single unit. On top is an A3 style flat top allowing the use of several sighting options. The front sight is a standard A2 sight assembly and can be combined with several popular rear sighting or BUIS (Back Up Iron Sight) devices, and even used in conjunction with a plethora of low magnification, electronic sights.
Since we had a positive experience with the BW Optic Y-TAC scope the last time we tested the LR-308, it was decided to use it again in with new configuration. The BW Optic Y-TAC used in this article was a 2.5 to 10-power scope with a 42mm objective. These scopes are custom built by IOR Bucuresti in Bucharest, Romania. The photoengraved German glass used in the assembly of the Y-TAC features the Carl Ziess T-3 lens coating system and combined with the 30mm tube it provides an excellent sight, especially when multiple loads are to be used. With a scope of this nature it is easy to “zero” a specific load and have several different points of aim to use for specialty rounds and always be “on” without firing multiple test shots when in the field. We will get into a little more detail on multiple loads and point of aim vs. point of impact later in the article.
The barrel of the AP4 may be shorter and the overall gun much lighter than the original LR-308 but don’t be fooled into thinking the changes were made at the expense of the performance. The 16-inch 4140 Chrome-moly steel barrel is contained inside a free floating handguard and is still a button rifled, 6-groove, 1 in 10-inch twist. The shorter barrel is completed with 308 Panther flash hider, which is attached via a standard 5/8×24 thread. This last little detail brought immediate joy to the author who contacted suppressor manufacturer Elite Iron and immediately ordered their D30 silencer to test in conjunction with this rifle.
Dale and Kathy Poling of Elite Iron have been involved in the machine gun and suppressor industry for several years. Their latest suppressor line, including the D22 and D30, are made with 304 stainless steel tubes and all internals are CNC machined from solid billet stainless steel. Upon assembly they are welded for added strength and durability. They can immediately be identified by their signature-knurled bands at the rifle end of the suppressor. Throughout our testing, the DPMS LR-308AP4 and the Elite Iron D30 silencer proved to be an excellent combination.
Time at the range was spent with several types of ammunition. Other than a few failures to feed due to a damaged magazine (which was quickly identified and discarded) the function of the LR-308AP4 was excellent and uneventful. We used Wolf 150-grain FMJ, 173-grain M118 Lake City Special Ball and 168-grain Federal Gold Medal. While all functioned well and performed satisfactorily, the combination of the DPMS LR-308AP4, fitted with the Elite Iron D30 Silencer and loaded with the Federal Gold Medal ammo provided most excellent results.
When changing muzzle devices the point of impact is almost always affected and we wanted to measure this effect with a single type of ammo for maximum continuity. After shooting a few groups we chose the Federal Gold Medal to continue recording and we started measuring group size and point of impact shift. We first sighted the rifle in with no muzzle device. We reinstalled the factory Panther flash hider and shot a 5-shot group at 100 yards. It measured 1.56 inches and was centered 2.8 inches low and left of the point of aim (in the 7 o’clock position). We were thinking that 1.5 MOA was pretty impressive for a 16-inch barreled, semiautomatic rifle fired in a semi-rapid manor but things were about to get better. The second group we fired was done without any muzzle device and we again shot a 5-shot group at 100 yards. The point of impact was exactly the point of aim and the group measured an impressive 1.10 inches. Things just continued to get better. The Elite Iron D30 Silencer was attached and we fired a third 5-shot group. This time the point of impact shifted 3 inches to the right of the point of aim (in the 3 o’clock position) and measured an amazing .765 inches. Since we were shooting 5-shot groups we were impressed with this combination and continued to shoot the same point of impact for the remainder of the afternoon.
Point of Impact vs. Point of Aim
Since it was brought up earlier, a little more should be said about this effect. Contrary to some beliefs, almost anything you do with a firearm in relation to the barrel can affect the point of impact. In the field of precision shooting there are several factors that determine exactly where the bullet is going to impact once the trigger is squeezed. Most are related to the shooter but even after the human factor is taken out there are many more forces at play. The harmonics and whip of the barrel change every time an accessory is added or removed. Most are sensitive enough that even the use of a bipod placed directly on the barrel instead of the stock can have a dramatic effect on accuracy. At times, removing and replacing the same accessories without tightening them the same can even show a slight difference in the group size or placement. Typically the whip effect of a barrel is more exaggerated or pronounced if the barrel is a long or thin barrel (or a combination of both) and lessened with a short and fat barrel, hence the popularity of “bull” barrels with serious target shooters.
Even though barrels tend to react differently to dissimilar stocks, loads or muzzle devices, they usually have some amazing continuity if those factors are not disrupted. That being said, once a firearm is setup the way the shooter wants to use it, leaving it alone is the best cure. When an accessory is added and the point of impact has shifted, all the shooter needs to do is re-zero the firearm with the new combination of parts. A look at the combination of the LR-308AP4 and the Elite Iron D30 Silencer is an excellent example of a situation when the performance can actually be improved. The group size was almost reduced by one half, dropping from 1.5 inches to almost 3/4 of an inch, consistently. All that was necessary was a re-zero of approximately 3 inches to the left and this mighty carbine was transformed into an extremely quiet, sub-MOA powerhouse. To be sure of your sighting, just make sure that every time changes are made to any portion of the system, recheck the zero.
Just before going to press we were informed by Dale Poling at Elite Iron that he has developed a system of “tuning” a rifle and suppressor so POI shift will be minimal, if measurable at all. According to Poling, using his method, if there is any POI shift it tends to be minimally vertical with no apparent horizontal shift at all. For more information on this latest finding you can contact Dale directly via e-mail at: Kpoling@Blackfoot.net
Point of impact is obviously also affected by the ammo you are using. Just like the examples explained above, a different load can produce as tight a group as the first, but if it isn’t hitting the intended area it has little value to the shooter. One example where 2 different loads may be advantageous to a shooter would be when utilizing subsonic ammo for specialty applications and finding it necessary to also use high velocity ammo for other situations. During some earlier testing with subsonic ammunition for Small Arms Review (Vol. 9, No 9, June 2006) we fired a substantial amount of Engel Ballistic Research 7.62x51mm Thumper. This 180-grain projectile traveling at an average of 958 feet per second would consistently (and silently) impact the target at 6 inches below the point of aim established for the full strength projectile traveling at 2,642 feet per second. The windage was not affected at all. With the sound reduction being a big factor in some instances and the consistency being so tight, all the shooter has to do is choose a mil-dot with a 6-inch rise as the point of aim for use with the subsonic ammo, and aim directly at the target. When it becomes desirable to use the high velocity ammo again, the shooter just returns to using the original point of aim. The BW Optic Y-TAC is an excellent choice for an application such as this. The Leupold M8 Tactical Mil-Dot scope also works quite well for multi-load uses. With a little practice and an understanding of your firearm and ammo, it is amazingly simple and effective.
Even though the LR-308AP4 with the 16-inch barrel is much smaller and lighter than the original LR-308 with the 24-inch bull barrel, the performance is still extremely impressive. The threaded muzzle allows for the use of many accessories and the AP4 returns more traditional cosmetic features that some black rifle enthusiasts find desirable. The available telescopic stock allows for a smaller package when carrying or transporting and has a similar feel to the original M4. Based on the original ArmaLite AR10 design, there are several magazines available in a number of materials and capacities, and they are reliable and inexpensive. Being a life-long fan of the black rifle as well as a student of the “School of Bigger is Better,” this writer thoroughly enjoyed testing the LR-308AP4. Combined with the Elite Iron D30 Silencer it well surpassed any preconceived accuracy expectations and the combination is destined to become permanent fixtures in the Small Arms Research reference collection. With a suggested retail of $1,254, this rugged and well-built carbine is sure to make an excellent addition to the collection or any black rifle enthusiast.
3312 12th Street SE
St. Cloud, MN 56304
1345 Thunders Trail
Bonner, MT 59823
P.O. Box 355
Simpsonville, SC 29681
EBR Subsonic Ammo
Engel Ballistic Research
544 Alum Creek Rd.
Smithville, TX 78957
|This article first appeared in Small Arms Review V10N12 (September 2007)|
and was posted online on November 16, 2012