The AR-15 is able to reproduce itself by entering a safe. This phenomenon, which is well-documented, can occur as soon as it enters a safe. We tell our significant other that the basic 16-inch-barreled AR-15 is the best. It can do most things well, but it doesn’t excel in any particular role. Once you have that AR, you can move on to more advanced versions like the one shown here. We chose to go down the DMR rabbit hole because it’s fun to poke holes in things at longer ranges. This combination is the best combination in terms of reliability and velocity using the 5.56x45mm ammunition. The gas port pressures are lower due to the increased distance from the chamber. The sub-assemblies aren’t as beaten up as those with longer, higher-pressure gas systems. This is in contrast to a 10.3-inch Mk18 rifle with a carbine length tube. The 20-inch rifle has a more relaxed attitude. Imagine the ’78 Lincoln Continental versus the ’05 Subaru STI. The barrel is now a little shorter, but the rifle-length gas system is retained. This results in a more user-friendly carbine that has a softer recoil impulse and is easier to use. We chose an 18-inch barrel with FN’s government profile. It is chrome lined and button rifled. This barrel offers a good balance between accuracy, longevity, and wallet-friendliness. Although it won’t be seen at any benchrest competitions, we are happy to trade a few tenths an inch in group size in exchange for dollars in our bank accounts. It’s also possible to trade a few tenths of an inch in group size for dollars. The package includes a magnetic particle inspection, Carpenter 158 bolt (also NiB-coated), which assures us that the bolt will be as durable as the barrel. This gun is DMR-ish so we had to think about a bipod. Caldwell has a 15-inch free-float tube that provides plenty of real estate and M-lok slots for lights, sling mounts, and other accessories. We ordered an MFT Minimalist set with a QD Endplate. This was then screwed into a lower receiver by Orchid Defense Group. We don’t usually get excited about standard lowers, as they’re just an aluminum box that holds the fun bits together. But this one is different in that it’s a low-shelf variant and has all the machining that you’d normally find on an M16 receiver, except the third hole. If you’re a 07 FFL holder, this is good information to keep in your mind.Human Interface
Once all the components were in place it was time for us to focus on the two most important pieces of kit in terms of human interface or getting hits on steel: the scope and trigger. Rise Armament’s S140 trigger offers exceptional value for money. It’s made from S7 tool steel, has a 3.5-pound break, zero take up, and a quick reset. This trigger is available for $139. We decided to go with Primary Arms’ SLX3-18×50 glass because it was the most affordable. Wheeler Engineering’s FAT wrench makes it easy to set the correct torque settings. No more broken tubes or shifting scopes. Only a decade ago, glass made to this standard would have cost thousands of dollars. But, Primary Arms has managed to bring it to market for a mere 500 bucks. The ACSS reticle is one of its most useful features. It is calibrated for 5.56 projectiles, and is located in the first focal plane. This allows the shooter to use its BDC hashmarks at any magnification. You can lift the locking elevation turret up and spin away. We had no problems tracking; every time we returned to zero our point of impact was true. The illuminated reticle makes it easier to hit targets in low light conditions. It can also be used at low magnification for quick shots. Simply use the thick central horseshoe portion of the reticle and frame the target. The image quality was slightly less than high-end scopes. However, it is four times more expensive than the primary arms glass. Grab a toolkit and join the fun.
Once all components were assembled, it was time for everything to be put together. The Tipton gun vise was a great help. We were able to finish the build in record time with no dings or buggered parts thanks to the Wheeler Engineering scope mounting kits. This combo is great for anyone who mounts many scopes. It saves time and ammunition. The rifle wouldn’t cycle the Wolf 55-grain steel cases we tried initially. It ejected spent cases but failed to kick the BCG far enough back to pick up a new cartridge. A few mags were run through the rifle to get it used to M193-spec loads. The rifle ran well on OTM ammo SIG 77-grain OTM ammo. We also verified zero on paper. After that, we ran it 600 yards on steel to verify that it fulfills the DMR role. You could add an offset red-dot, a muzzle brake and you’d be able to hang with your friends at a three gun match. However, you’d be competing in Open division, which means you would need an optic-equipped pistol with compensator. Sources:
Primary Arms
Rise Armament
Tipton
WheelerEditor’s note: This article first appeared in Gun Digest the Magazine, November 2021. Download your Storm Tactical Printable Target pack62 Printable MOA Targets and DOT Drills for rifle and handgun range. Target grids and bullseye sizes can be found in MOA. Get Free Targets
