Inside 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 truthful, well-informed answer, not simply sales pitches. Robert Whitley posted an incredibly comprehensive answer to this question, based on his experience building and testing dozens of best AR-15 collapsible stock. Robert runs AR-X Enterprises, which produces match-grade uppers for High Power competitors, tactical shooters, and varminters.
There are a lot of things that can be done to a AR to further improve consistent accuracy, and so i utilize the words “consistent accuracy” because consistency is an element of it (i.e. a good amount of guns will give a few great 5-shot groups, but won’t do a good 10- or 20-shot groups, and a few guns will shoot great 1 day and not so excellent on others).
Listed here are 14 key things we think are crucial to accuracy.
1. Great Barrel: You’ll need a premium match-grade barrel, well-machined with a good crown along with a match-type chambering, true towards the bore and well cut. The extension threads also must be cut true towards the bore, with everything else true as well as in proper alignment.
2. Rigid Upper: A rigid, heavy-walled upper receiver aids accuracy. The normal AR upper receiver was made for any lightweight carry rifle and so they stripped all of the metal they can off it so it will be light to carry (that is advantageous for that military). The internet result are upper receivers which are so thin you are able to flex them your bare hands. These flexible uppers are “strong enough” for general use, but are not ideal 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 point but it is always better to keep everything linked to the barrel and the bore in complete alignment together with the bore (i.e. barrel extension, bolt, upper receiver, carrier, etc.).
4. Barrel Extension: You ought to Loctite or glue the barrel extension to the upper receiver. This holds it in position all the way front to back in the upper receiver. Otherwise if there is any play (there typically is) it merely hangs around the face of your upper receiver completely determined by the face area from the upper receiver as the sole method to obtain support to the barrel in contrast to being made more a fundamental element of the upper receiver by being glued-in.
AR-X AR15 Upper5. Gas Block: You will want gas block that does not impose pointed stress around the barrel. Clamp-on types that grab entirely around the barrel are great. The blocks that happen to be pinned up with tapered pins that wedge against the barrel or the slip on sort of block with set screws that push up from underneath (or entirely on the barrel) can deform the bore inside the barrel and can wreck the precision of your otherwise great barrel.
6. Free-Float Handguard: A rigid, free-float handguard (and i also emphasize the word rigid) really makes a difference. There are numerous types of free-float handguards as well as a free-float handguard is, in as well as itself, an enormous improvement more than a non-free-float set up, but best is a rigid set-up. A number of the ones in the marketplace are small diameter, thin or flexible and when you are shooting off almost any rest, bipod, front bag, etc., a rigid fore-end is better since ARs want to jump, bounce and twist once you let a go go, as being the carrier begins to begin its cycle prior to the bullet exits the bore.
7. Barrel Contour: You want some meat in the barrel. Between the upper receiver along with the gas block don’t go real thin having a barrel (we like 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 that offers vibrations and stress around the barrel, especially involving the gas block straight back to the receiver. A heavier barrel here dampens that. Staying a little heavier with barrel contour from the gas block area and to the muzzle will work for a similar reasons. ARs use a lot happening once you touch off a round along with the gas system pressures up and the carrier starts moving (all ahead of the bullet exits the bore) therefore the more situations are made heavier and rigid to counteract that 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 through the barrel nut, throughout the front from the upper receiver, and through the gas key inside the carrier. Make sure the gas tube is not impinged by any kind of them, in order that it is not going to load the carrier in a stressed orientation. You don’t want the gas tube bound up in order that as soon as the gas tube pressures up it immediately desires to transmit more force and impulse on the barrel than would normally occur. We sometimes spend a 63dexjpky of your 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 obtain them right – factory tubes may work OK however 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 helps to make the gas system pressure up earlier and a lot more aggressively. This will cause more impulse, and increases forces and vibration affecting the very best end along with the barrel. Tune the gas port to give the volume of pressure necessary to function properly and adequately but no more.
10. Front/Back Bolt Play: If accuracy will be the game, don’t leave a lot of front/back bolt play (make it .003? but no more than .005?). We’ve seen factory rifles run .012? to .015? play, which can be OK if you wish to leave room for grime and dirt within a military application. However, that level of play is not ideal for a higher-accuracy AR build. Plenty of front/back bolt play allows rounds being hammered into the chamber and actually re-formed inside a non-consistent way, as they are loaded in to the chamber.
11. Component Quality: Use good parts from your reputable source and also be wary of “gun show specials”. All the parts usually are not a similar. Some are good, some are not so excellent, and several aftermarket parts are simply just bad. Don’t be afraid to make use of mil-spec-type carriers; by and large these are excellent for an accuracy build. Also, understand that simply because a carrier says “National Match” or anything else onto it does not always mean it’s any better. Be skeptical of chrome-plated parts because the chrome plating can transform the various components dimensionally and may also ensure it is difficult to do hand-fitting for fit and performance.
12. Upper to lessen Fit: A great upper/lower fit is effective. For fast and dirty fit enhancement, an Accu-Wedge within the rear helps a lot. The ultimate solution is to bed the top into a specific lower so that the upper and lower, when together, are more like one integral unit. For that upper receivers we produce, we try to have the specs as near as we can, but nevertheless fit the different lowers on the market place.
13. Muzzle Attachments: Don’t screw within the muzzle (literally). Leave the maximum amount of metal in the barrel at the muzzle as possible. People like to thread the muzzle to get a flash hider, suppressor, muzzle brake, or some other attachment, however if you want accuracy, leave the maximum amount of metal as you can there. And, if you have something that screws on, set it up so that it may be put on and possess it stay there without putting plenty of torque and stress on it right the location where the bullet exits the bore. If you are intending to thread the end from the barrel, ensure it is concentric together with the bore and ensure everything you screw on the website is just as well. For those muzzle attachments, also be sure that the holes through which the bullet passes through are dead true towards the bore. Many aftermarket screw-on the situation is not good this way. Something that vents gas should vent symmetrically (i.e. if it vents left, it should vent equally right, and likewise, if this vents up, it will vent down equally). Uneven venting of gas can wreck accuracy.
14. Quality Ammunition: Ammo is really a whole story itself, but loads that happen to be too hot typically shoot poorly in upper receiver for sale. If you need accuracy out from an AR-15, avoid overly hot loads. Shown below are test groups shot with four (4) different uppers, all with moderate loads. These four uppers all virtually had exactly the same features and things performed to them as explained in this post, plus they all shot great.