Within our Shooters’ Forum, one member recently asked: “What makes an AR accurate? What parts upon an AR really can affect accuracy – like free-floating handguards, barrels, bolts, bolt carriers?” He wanted a genuine, well-informed answer, not simply sales pitches. Robert Whitley posted an incredibly comprehensive answer to this inquiry, based on his experience building and testing lots of best AR15 manufacturers. Robert runs AR-X Enterprises, which produces match-grade uppers for top Power competitors, tactical shooters, and varminters.
There are tons of things that you can do with an AR to enhance consistent accuracy, and that i take advantage of the words “consistent accuracy” because consistency is an element of it (i.e. a good amount of guns will provide several great 5-shot groups, but won’t do an excellent 10- or 20-shot groups, and a few guns will shoot great a day and never so excellent on others).
Here are 14 key things we think are important to accuracy.
1. Great Barrel: You’ll desire a premium match-grade barrel, well-machined with an excellent crown as well as a match-type chambering, true for the bore and well cut. The extension threads must also be cut true to the bore, with everything true and also in proper alignment.
2. Rigid Upper: A rigid, heavy-walled upper receiver aids accuracy. The standard AR upper receiver was created for the lightweight carry rifle and they also stripped all of the metal they can off it to make it light to handle (which happens to be advantageous for that military). The internet result are upper receivers that happen to be so thin it is possible to flex all of them with your bare hands. These flexible uppers are “strong enough” for general use, however are not ideal for accuracy. Accuracy improves by using a more rigid upper receiver.
3. True Receiver Face: We’ve learned that truing the receiver face is valuable. Some may argue this aspect however it is always better to keep everything related to the barrel and also the bore in complete alignment using the bore (i.e. barrel extension, bolt, upper receiver, carrier, etc.).
4. Barrel Extension: You must Loctite or glue the barrel extension in to the upper receiver. This holds it into position all the way up front to during the upper receiver. Otherwise if you find any play (where there typically is) it merely hangs in the face of your upper receiver completely dependent on your face from the upper receiver as the sole way to obtain support for your barrel in contrast to being made more a fundamental element of the upper receiver when you are glued-in.
AR-X AR15 Upper5. Gas Block: You desire a gas block that fails to impose pointed stress in the barrel. Clamp-on types that grab entirely round the barrel are fantastic. The blocks that are pinned up with tapered pins that wedge from the barrel or maybe the slip on type 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 accuracy of the otherwise great barrel.
6. Free-Float Handguard: A rigid, free-float handguard (and so i emphasize the term rigid) really is important. There are numerous types of free-float handguards and a free-float handguard is, in as well as itself, a massive improvement over a non-free-float set up, but best can be a rigid set-up. Some of the ones available on the market are small diameter, thin and flexible and should you be shooting off almost any rest, bipod, front bag, etc., a rigid fore-end is most beneficial since ARs wish to jump, bounce and twist once you let an attempt go, since the carrier begins to begin its cycle just before the bullet exits the bore.
7. Barrel Contour: You desire some meat around the barrel. Between the upper receiver along with the gas block don’t go real thin using a barrel (we like 1? diameter if it’s workable weight-wise). When you touch off a round along with the bullet passes the gas port, the gas system immediately starts pressuring up with a gas impulse that gives vibrations and stress about the barrel, especially in between the gas block to the receiver. A heavier barrel here dampens that. Staying a little bit heavier with barrel contour through the gas block area and out to the muzzle is good for the same reasons. ARs have a lot going on whenever you touch off a round along with the gas system pressures up and also the carrier starts moving (all prior to the bullet exits the bore) and so the more the situation is made heavier and rigid to counteract how the better – within reason (I’m not advocating a 12-lb barrel).
8. Gas Tube Routing Clearance: You desire a gas tube that runs freely from the barrel nut, from the front from the upper receiver, and thru the gas key in the carrier. Make sure the gas tube is not really impinged by some of them, in order that it is not going to load the carrier inside a stressed orientation. You don’t want the gas tube bound up to ensure once the gas tube pressures up it immediately would like to transmit more force and impulse for the barrel than would normally occur. We sometimes spend a 63dexjpky of your energy moving the gas block with gas tube on and off new build uppers and tweaking gas tubes to have proper clearance and alignment. Most gas tubes do need some “tweaking” to get them right – factory tubes may work OK nonetheless they typically will not function optimally without hand-fitting.
9. Gas Port Tuning: You would like to avoid over-porting the gas port. Being over-gassed makes the gas system pressure up earlier plus more aggressively. This will cause more impulse, and increases forces and vibration affecting the best end and also the barrel. Tune the gas port to present the volume of pressure needed to function properly and adequately but no longer.
10. Front/Back Bolt Play: If accuracy is the game, don’t leave plenty of front/back bolt play (ensure that it stays .003? but no more than .005?). We’ve seen factory rifles run .012? to .015? play, that is OK if you need to leave room for grime and dirt in a military application. However, that amount of play is not ideal for a higher-accuracy AR build. Lots of front/back bolt play allows rounds to get hammered in to the chamber and re-formed inside a non-consistent way, as they are loaded in the chamber.
11. Component Quality: Use good parts from a reputable source and be wary of “gun show specials”. All parts are NOT the same. Some are perfect, some will not be so excellent, plus some aftermarket parts are simply just bad. Don’t hesitate to make use of mil-spec-type carriers; in general they can be good for an accuracy build. Also, do not forget that even though a carrier says “National Match” or something else on it does not necessarily mean it’s any better. Be skeptical of chrome-plated parts as the chrome plating can transform the various components dimensionally and might also allow it to be difficult to do hand-fitting for fit and function.
12. Upper to lessen Fit: A great upper/lower fit is helpful. For quick and dirty fit enhancement, an Accu-Wedge within the rear helps a great deal. The best option is to bed the upper to some specific lower in order that the upper and lower, when together, are definitely more like one integral unit. For the upper receivers we produce, we attempt to obtain the specs as near since we can, but nonetheless fit the various lowers available in the market place.
13. Muzzle Attachments: Don’t screw in the muzzle (literally). Leave the maximum amount of metal in the barrel with the muzzle that you can. People want to thread the muzzle to get a flash hider, suppressor, muzzle brake, or some other attachment, but when you want accuracy, leave the maximum amount of metal since you can there. And, in case you have an issue that screws on, set it up in order that it may be put on and possess it stay there without putting a great deal of torque and stress upon it right in which the bullet exits the bore. If you are intending to thread the conclusion in the barrel, allow it to be concentric together with the bore and ensure what you screw on there is really as well. For all those muzzle attachments, also be sure that the holes through which the bullet passes through are dead true for the bore. Many aftermarket screw-on situations are not good that way. Everything that vents gas should vent symmetrically (i.e. if this vents left, it ought to vent equally right, and likewise, when it vents up, it should vent down equally). Uneven venting of gas can wreck accuracy.
14. Quality Ammunition: Ammo is really a whole story itself, but loads that are too hot typically shoot poorly in best AR15 manufacturer. If you wish accuracy out 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 the identical features and things performed to them as explained in the following paragraphs, and they also all shot great.