I recently built out a multi-gun AR on a pre-ban lower in an effort to create a rifle that would be more suited to shooting multi-gun competitions. I find that the full top-to-bottom of the parts selection process isn’t always discussed thoroughly, so that got me thinking that I should lay all of that out.
After the break are the elements of my “high-speed” AR, with some explanation of why I chose them.
Muzzle Brake/Comp: You need to minimize muzzle rise and recoil. Sound, dust, etc. are just not concerns. I grabbed a VG6 Gamma brake for forty bucks that greatly reduces both muzzle rise and recoil, to the point where the muzzle rise is essentially nil if you’ve got a good C-clamp on the handguard. There are other brakes that are no doubt more effective, but it’s hard to imagine a better cost-benefit-weight ratio.
Adjustable Gas: In a defensive firearm, absolute reliability is key. It must go bang every time no matter how dirty it is, preferably with whatever ammo you can find. But on a competition rifle, that’s not such an ironclad demand. Reducing the amount of gas going into the action will reduce recoil. You want as little recoil as you can get away while still keeping your gun cycling. Superlative, SLR, and Wojtek are all great choices. I chose the Superlative; it’s not terribly expensive, and the detent-controlled adjustment is nice. I am a little skeptical of the bleed-out mechanism, but it doesn’t seem to hurt.
Lightweight Bolt Carrier Group: Less bolt carrier mass means less mass moving back and forth, but that mass is going to go at higher speed. BUT, when combined with an adjustable gas system, you can reduce that velocity somewhat, and get a net decrease in recoil. I went with the RTB lightweight BCG. Brownells also makes a similarly inexpensive lightweight BCG.
18″ Barrel with Mid-length or rifle gas: If you’re buying a new barrel, make it 18″ and get one with mid-length or rifle gas (preferably the latter). The 18″ barrel will give you just a touch more velocity, which is helpful when using BDC reticles. The longer gas system will further smooth out the recoil pulse. And, this should go without saying, but you want the most accurate barrel you can find. My choice was the lightweight 18″ Criterion barrel that is a Midwest Industries exclusive.
Handguard: Make your handguard as long and lightweight as possible so you can C-clamp it as far out as possible. I chose the Aero enhanced uppers with their 15″ handguards – they’re not too expensive, they’re not too heavy, they’re not too fat, and they’re stupidly easy to install. The Aero enhanced uppers also have a handguard mounting system that makes the barrel even more resistant to deflection (since the handguard isn’t even attached to the barrel nut).
Trigger: I used to believe that the trigger was not super-important so long as it wasn’t mil-spec, but after using the Hiperfire Hipertouch Eclipse, I’ve become a believer. The Hipertouch Eclipse and Competition triggers are both superb, but the LaRue MBT-S, Geiselle SSA-E/S3G, and Geiselle SD-E/SD-3G are all very viable options.
Buffer System: I like the Vltor A5H0 system when running a lightened carrier, but Taccom also makes an ultra-light buffer for standard carbine tubes that works quite well. In particular, I’m using BCM’s A5H0 buffer kit, which comes with the tube, buffer, spring, and end plate items. Some people also go with lightened buffer springs; you need to be careful of doing this, because if you rob your buffer system of too much power, you will begin to have failures to feed. While competition guns don’t need the kind of all-conditions-all-the-time reliability that a defensive firearm needs, you still need enough to get through a match 100% of the time.
Stock: I like to run my guns light-weight, so the MFT Minimalist stock was my choice. If I had not been running the A5 buffer system, the Odin Works Zulu 2.0 probably would have been my pick.
Primary Sighting System: I’m using a Vortex Razor Gen3 with MOA reticle. However, the choice depends on what equipment division you’re in. If you’re in a scope-capable class, an LPVO like the Vortex Razor Gen 2/3 or C-More C3 is a very good choice, and there are also excellent scopes from Kahles (K16i/K18i) and Swarovski (Z6i/Z8i) that are worth considering if you have the money. If you are in a division where red dots are the only choice (such Tac Limited) or you’re not shooting far (USPSA PCC), I would strongly recommend a C-More ATRW, simply because it is VERY easy to use with both eyes open and obscures very little of your field of view. Otherwise, the Eotech holographic sight and Holosun HS510C are both very good options.
Secondary / Near-Distance Sighting System: Most people running LPVOs will choose Magpul Pro offset iron sights – which is what I did – or maybe fixed offset sights (I’ve heard these have fallen out of favor a bit), but if you are in an open/unlimited division, you will want an offset red dot. You have a lot of choices there, but most people seem to run an offset “Micro-style” red dot or an RMR. Mount choices for those are myriad, but the Arisaka is pretty popular. You could also use a Warne RAMP mount or similar modular mount for your optic combo, but be advised that there are a lot of considerations to running an integrated setup – for example, it’s sometimes difficult to operate left-side switches and knobs. If you’re running a reflex sight as your primary, I would not bother with a secondary sighting system… if it goes down, your match, from a competitive viewpoint, is basically over anyways.
(In case you were wondering, the rail on the very front of my handguard was used for mounting a Magnetospeed V3 so I could chrono my ammo.)
Put together, it’s a really terrific gun!
It’s not necessarily the lightest gun out there, albeit it’s still a lot lighter than you might expect. But recoil is extremely light, so it’s a bullet hose on up close target arrays, and it’s accurate with enough magnification top-end to go any distance you need to. And provided you stay within the ammo constraints required by the tweaked gas system and give it a bit of lube, it’s also extremely reliable.
(If I were going to change it around to focus more on reliability than recoil reduction, I would use a fixed gas block, a LMT enhanced BCG, and an A5H2 buffer system.)