In our Shooters’ Forum, one member recently asked: “What makes an AR accurate? What parts with an AR can actually affect accuracy – such as free-floating handguards, barrels, bolts, bolt carriers?” He wanted a genuine, well-informed answer, not merely sales pitches. Robert Whitley posted an incredibly comprehensive response to this, according to his experience building and testing lots of upper receivers vs. lower receivers. Robert runs AR-X Enterprises, which produces match-grade uppers for top Power competitors, tactical shooters, and varminters.
There are a lot of things that you can do to an AR to boost consistent accuracy, and I use the words “consistent accuracy” because consistency is an integral part of it (i.e. a lot of guns will give a couple great 5-shot groups, but won’t do a very good 10- or 20-shot groups, plus some guns will shoot great a day instead of so good on others).
Listed here are 14 key things we believe are essential to accuracy.
1. Great Barrel: You’ll want a premium match-grade barrel, well-machined with a decent crown plus a match-type chambering, true for the bore and well cut. The extension threads must also be cut true towards the bore, with everything else true and also in proper alignment.
2. Rigid Upper: A rigid, heavy-walled upper receiver aids accuracy. The common AR upper receiver was created for a lightweight carry rifle and they stripped each of the metal they might off it so it will be light to transport (which happens to be advantageous to the military). The world wide web result are upper receivers which are so thin you are able to flex them with your bare hands. These flexible uppers are “strong enough” for general use, however they are not suitable for accuracy. Accuracy improves having a more rigid upper receiver.
3. True Receiver Face: We’ve found that truing the receiver face is valuable. Some may argue this time however it is always advisable to keep everything associated with the barrel and the bore in complete alignment with all the bore (i.e. barrel extension, bolt, upper receiver, carrier, etc.).
4. Barrel Extension: You need to Loctite or glue the barrel extension into the upper receiver. This holds it in position completely front to during the upper receiver. Otherwise if you find any play (there typically is) it just hangs in the face from the upper receiver completely determined by the face of your upper receiver as the sole method to obtain support to the barrel in contrast to being made more a fundamental part of the upper receiver when you are glued-in.
AR-X AR15 Upper5. Gas Block: You need a gas block that fails to impose pointed stress on the barrel. Clamp-on types that grab completely across the barrel are great. The blocks that are pinned on with tapered pins that wedge against the barrel or the slip on sort of block with set screws that push up from underneath (or right on the barrel) can deform the bore inside of the barrel and can wreck the precision of the otherwise great barrel.
6. Free-Float Handguard: A rigid, free-float handguard (and I emphasize the word rigid) really is important. There are numerous varieties of free-float handguards plus a free-float handguard is, in and also itself, an enormous improvement over a non-free-float setup, but best is a rigid set-up. Some of the ones available on the market are small diameter, thin and/or flexible and in case you are shooting off any type of rest, bipod, front bag, etc., a rigid fore-end is most beneficial since ARs desire to jump, bounce and twist once you let a try go, as the carrier begins to begin its cycle ahead of the bullet exits the bore.
7. Barrel Contour: You desire some meat in the barrel. Involving the upper receiver and also the gas block don’t go real thin by using a barrel (we love 1? diameter if it’s workable weight-wise). Once you touch off a round and the bullet passes the gas port, the gas system immediately starts pressuring on top of a gas impulse which offers vibrations and stress about the barrel, especially involving the gas block back to the receiver. A heavier barrel here dampens that. Staying a little bit heavier with barrel contour throughout the gas block area and to the muzzle will work for exactly the same reasons. ARs use a lot going on once you touch off a round along with the gas system pressures up and also the carrier starts moving (all just before the bullet exits the bore) and so the more things are made heavier and rigid to counteract the better – within reason (I’m not advocating a 12-lb barrel).
8. Gas Tube Routing Clearance: You need a gas tube that runs freely with the barrel nut, through the front in the upper receiver, and thru the gas key from the carrier. Ensure that the gas tube will not be impinged by some of them, to ensure that it is not going to load the carrier in the stressed orientation. You don’t want the gas tube bound up so that once the gas tube pressures up it immediately desires to transmit more force and impulse towards the barrel than would normally occur. We sometimes spend a 63dexjpky of energy moving the gas block with gas tube off and on new build uppers and tweaking gas tubes to obtain proper clearance and alignment. Most gas tubes do need a little “tweaking” to have them right – factory tubes may work OK nonetheless they typically tend not to function optimally without hand-fitting.
9. Gas Port Tuning: You need to avoid over-porting the gas port. Being over-gassed definitely makes the gas system pressure up earlier and much more aggressively. This causes more impulse, and increases forces and vibration affecting the very best end along with the barrel. Tune the gas port to give the level of pressure found it necessary to function properly and adequately but forget about.
10. Front/Back Bolt Play: If accuracy may be the game, don’t leave lots of front/back bolt play (keep it .003? but not more than .005?). We’ve seen factory rifles run .012? to .015? play, that is OK if you wish to leave room for dirt and grime in the military application. However, that quantity of play is not ideal for an increased-accuracy AR build. A great deal of front/back bolt play allows rounds to get hammered in to the chamber and also re-formed in the non-consistent way, because they are loaded in the chamber.
11. Component Quality: Use good parts from your reputable source and also be wary of “gun show specials”. All parts usually are not the identical. Some are excellent, some are not so excellent, and a few aftermarket parts are simply bad. Don’t hesitate to utilize mil-spec-type carriers; in general these are excellent for an accuracy build. Also, understand that just because a carrier says “National Match” or anything else into it does not necessarily mean it’s any better. Be skeptical of chrome-plated parts since the chrome plating can change the parts dimensionally and can also allow it to be difficult to do hand-fitting for fit and function.
12. Upper to lessen Fit: An excellent upper/lower fit helps. For fast and dirty fit enhancement, an Accu-Wedge in the rear helps a great deal. The best option is to bed the top to some specific lower in order that the lower and upper, when together, are definitely more like one integral unit. For the upper receivers we produce, we attempt to obtain the specs as close since we can, but nonetheless fit the various lowers in the market place.
13. Muzzle Attachments: Don’t screw the muzzle (literally). Leave the maximum amount of metal in the barrel with the muzzle as you can. People love to thread the muzzle to get a flash hider, suppressor, muzzle brake, as well as other attachment, however if you truly desire accuracy, leave just as much metal since you can there. And, for those who have something which screws on, set it up in order that it may be placed on and also have it stay there without putting lots of torque and stress onto it right where the bullet exits the bore. If you are intending to thread the end from the barrel, allow it to be concentric using the bore and make certain what you screw on the website can be as well. For all muzzle attachments, also ensure that the holes by which the bullet passes through are dead true on the bore. Many aftermarket screw-on things are not too good like that. Whatever vents gas should vent symmetrically (i.e. if it vents left, it ought to vent equally right, and likewise, if it vents up, it must vent down equally). Uneven venting of gas can wreck accuracy.
14. Quality Ammunition: Ammo is actually a whole story itself, but loads which can be too hot typically shoot poorly in AR-15 for sale. If you need accuracy from an AR-15, avoid overly hot loads. Shown listed here are test groups shot with four (4) different uppers, all with moderate loads. These four uppers all basically had a similar features and things carried out to them as explained in this post, and they also all shot great.