Purpose Driven AR15's: The Competition Setup

AR15's are arguably the most versatile weapons platforms in the world.  If you need a rifle to do work within 1000m, odds are, you can outfit the AR platform to work for you.  With that said, what parts and components make up an AR15 of the "competition" variety?  We as shooters constantly hear terms like "tactical" or "limited" thrown around when describing classes in Multigun competition, but rarely is a rifle being shot in either of these divisions "limited" or "tactical" (in the popular gun-nut definition of the term, meaning "practical").  Most of these "race guns" are purpose built down to the the size of the barrel's gas-port, so let's explore what exactly makes up a Race AR, and why those parts are chosen.  Further, I will explain the drawbacks of using such a purpose built weapon in roles other than competition.

The "Race AR" is a platform which first and foremost, is based heavily on recoil mitigation.  Parts are chosen and selected with the number one goal of muzzle control-ability in mind.  Parts integrally connected with recoil control and mitigation are:

1. The Muzzle Device
2. The Gas System
3. The Bolt Carrier Group
4. The Buffer System

1. The Muzzle Device - Compensators

The muzzle device on a Race AR will typically vary greatly from muzzle devices used in other "practical" applications.  Opposed to in these other applications, where flash suppression and concussive blast bare equal importance to recoil mitigation, in the competition world, there is virtually no reason to worry about suppressing flash or minimizing muzzle concussion/signature.  With this in mind, muzzle devices which redirect gasses exceptionally well (at the cost of creating a fireball and massive concussion perpendicular to the muzzle) may be, and are, readily used.

2. The Gas System - Adjustable Gas Blocks and Gas Ports

In order to abstain from a lengthy academic discussion on gas system length, allow me to state that carbine systems (the short gas system) produce a large gas impulse heading back into the weapon's action, midlength systems (longer than carbine systems) produce less gas impulse than carbine systems, and rifle length systems (the longest system) create little gas impulse.  The more of an impulse you have, the more likely the weapon is to be able to cycle, but also, the more recoil you will feel.  With this in mind, Race ARs typically are built around a rifle length system with a tuned gas port to perfectly regulate the exact amount of gas needed to cycle the weapon, OR, a midlength system with an adjustable gas block.  An adjustable gas block allows the user to cover/close off a portion of the gas port in order to regulate the amount of gas flow and therefore lessen the impulse.  Although some shooters do run various combinations of gas port size and adjustable gas blocks on various length gas systems, I have found that on a rifle system, if the rifle has a properly sized gas port (for the shooters load), then an adjustable gas block will not do much if anything to reduce impulse.  On a midlength system, I believe that there is still enough impulse to warrant using an adjustable gas block over simply a smaller gas port size.  With this said, when utilizing an adjustable gas block, the user MUST be sure the adjustment screw NEVER deviates or else, the weapon may not get enough gas to cycle, and turn into a single shot gun.  The same goes for a weapon utilizing a smaller gas port.  As the weapon gets dirty, remember that there is less gas heading back into the action to help the weapon cycle, and short stroking can become a problem.  The gas system and alterations made to the gas system are some of the primary factors which effect weapon reliability, and while reliability is important in Multigun, reliability after 1000 rounds shot in a swamp after filling the action with mud is not.  

3. The Bolt Carrier Group - Lightened Carriers

Swapping out the standard BCG with a lightened carrier is common practice in Race ARs...based on the discussion we just had on the gas system, can you think why this would be the case?  You guessed it - by lightening the carrier, the user can reduce the amount of gas required to push the carrier backwards and

cycle the weapon.  So does swapping out the carrier cause any serious disadvantages to the weapons function in practical application? - Not on a round to round basis, at least I haven't experienced any with thousands of round fired.  What can be an issue however, is the longevity of the carrier.  Because material is being removed from the carrier, it is, despite what anyone may say, being structurally weakened...not by much of course, but certainly it will wear out sooner than a milspec carrier made with the same materials.  Further, many lightened carriers have had the teeth for the forward assist removed; rendering the FA unusable. 

4. The Buffer System - Lightened Buffers and Harder Springs.

As you may have guessed by now, tuning the AR15s felt recoil is all about using as little gas as possible to cycle the action, which in turn means cutting down as much reciprocating mass as possible.  As was true for the BCG, the buffers on most Race ARs are lightened to allow for a lesser force requirement to cycle.  On the flip side, buffer springs are typical strengthened.  What this does is allow the buffer spring, not the buffer (and in turn the rear of the stock tube), to absorb the energy coming back from the gas impulse and the reciprocation of the BCG.  Further, having a +10% spring also allows for a noticeably faster return to battery which means that the recoil impulse is cut down to a shorter time frame rather than a long drawn out push.  In short, it makes the impulse of the gun snappier, but despite how this might sound, this is desirable because it allows the gun to be driven back to target sooner (think standard AK v. Standard AR both chambered in .223...the AK has a long drawn out recoil impulse that doesn't feel like much, but keeps you off target whereas the AR has a shorter snappier impulse that appears to be more severe, but in actuality allows for faster accurate follow-up shots).

All the speed in the world isn't worth anything if the weapon isn't able to hold a a tight group.  The next aspect to the Race AR, much like other precision rifles, is a match grade barrel.  Most Race Gun setups run an 18" barrel or a 16" on the low end.  The barrel is ideally setup with a .223 Wylde chamber and a 1:8 twist rate in a SS platform.  The SS allows for increased accuracy over Chrome-lined.  The Wylde chamber allows for more case expansion than a .223 chamber, but also maintains great accuracy than the 5.56 chamber.  18" barrels tend to be the ticket right now in 3 Gun as they provide a a platform suitable for rifle length gas, while also being shorter than their 20" counterparts.  With a longer barrel, fluting or dimpling is also commonplace in an attempt to cut down on weight and to maintain an effective balance point.

Magnified optics or optics with a variable power capability are the primary difference separating "Tactical" and "Limited" class.  In Limited, only irons or 1X fixed power optics are legal.  In tactical, any single magnified optic is allowed.  Most Tactical shooters utilize a 1-4X or a 1-6X depending on budget.  Conversely, the Limited group is much more split, with some of the older shooters sticking with iron setups while the new guys have switched over to RDS.  Either way, no true race gun ever runs Back-Up sights; at least I've never seen it.  Back-up sights do little for a shooter utilizing his weapon in the confines of a flat range, and the removal thereof is a great way to shave off ounces from the rifle.  Obviously, if the rifle was going to be taken to do any serious practical work, the user would want to have some form of back-up sighting system.

With all this said, ARs and AR parts are harder than ever to find, thanks in large part to the political climate.  No matter what AR you have, you will be able to compete and have a good time, so go head out to a match!  While Race ARs allow for shooters at the top of the pack to cut down on their times even more, a rifle is only as effective as the shooter holding it.  Most of the best shooters out there could pick up an Oracle Carbine and continue to run far above most shooters who might bring said weapon to a match.  So, get out and practice until you have outgrown your current gear, and then move to upgrade.  Cheers all!