Within our Shooters’ Forum, one member recently asked: “What makes an AR accurate? What parts with an AR can really affect accuracy – like free-floating handguards, barrels, bolts, bolt carriers?” He wanted an honest, well-informed answer, not merely sales pitches. Robert Whitley posted a very comprehensive reply to this inquiry, based upon his experience building and testing dozens of AR-15 upper receiver for sale. Robert runs AR-X Enterprises, which produces match-grade uppers for High Power competitors, tactical shooters, and varminters.
There are a variety of things which can be done to a AR to further improve consistent accuracy, and I utilize the words “consistent accuracy” because consistency is an element of it (i.e. a lot of guns will provide a couple great 5-shot groups, but won’t do a very good 10- or 20-shot groups, and several guns will shoot great some day and not so excellent on others).
Allow me to share 14 key things we believe are essential to accuracy.
1. Great Barrel: You’ll require a premium match-grade barrel, well-machined with a good crown as well as a match-type chambering, true on the bore and well cut. The extension threads should also be cut true on the bore, with everything else true and then in proper alignment.
2. Rigid Upper: A rigid, heavy-walled upper receiver aids accuracy. The normal AR upper receiver was developed for any lightweight carry rifle and they also stripped all of the metal they could off it making it light to hold (which is advantageous to the military). The world wide web result are upper receivers that are so thin you are able to flex these with your bare hands. These flexible uppers are “strong enough” for general use, but they are not perfect for accuracy. Accuracy improves having a more rigid upper receiver.
3. True Receiver Face: We’ve found out that truing the receiver face is valuable. Some may argue this time however it is always better to keep everything related to the barrel along with the bore in complete alignment with all the bore (i.e. barrel extension, bolt, upper receiver, carrier, etc.).
4. Barrel Extension: You should Loctite or glue the barrel extension to the upper receiver. This holds it set up entirely front to during the upper receiver. Otherwise when there is any play (there typically is) it really hangs about the face in the upper receiver completely influenced by the face of your upper receiver as the sole supply of support to the barrel in contrast to being made more a fundamental element of top of the receiver when you are glued-in.
AR-X AR15 Upper5. Gas Block: You need a gas block that does not impose pointed stress about the barrel. Clamp-on types that grab completely throughout the barrel are fantastic. The blocks that happen to be pinned up with tapered pins that wedge up against the barrel or perhaps the slip on kind of block with set screws that push up from underneath (or right on the barrel) can deform the bore inside of the barrel and might wreck the accuracy of the otherwise great barrel.
6. Free-Float Handguard: A rigid, free-float handguard (and i also emphasize the phrase rigid) really makes a difference. There are many types of free-float handguards plus a free-float handguard is, in as well as itself, a tremendous improvement over a non-free-float put in place, 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 any kind of rest, bipod, front bag, etc., a rigid fore-end is advisable since ARs wish to jump, bounce and twist once you let an attempt go, as being the carrier begins to begin its cycle prior to the bullet exits the bore.
7. Barrel Contour: You desire some meat on the barrel. In between the upper receiver along with the gas block don’t go real thin having a barrel (we love 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 track of a gas impulse that offers vibrations and stress on the barrel, especially between the gas block straight back to the receiver. A heavier barrel here dampens that. Staying a little bit heavier with barrel contour from the gas block area and over to the muzzle is good for the identical reasons. ARs have got a lot going on if you touch off a round and also the gas system pressures up and also the carrier starts moving (all before the bullet exits the bore) and so the more things are 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 will want gas tube that runs freely throughout the barrel nut, with the front in the upper receiver, and through the gas key inside the carrier. Guarantee the gas tube is not impinged by any of them, in order that it will not load the carrier in the stressed orientation. You don’t want the gas tube bound up to ensure when the gas tube pressures up it immediately wants to transmit more force and impulse on the barrel than would normally occur. We sometimes spend a 63dexjpky of time moving the gas block with gas tube on / off new build uppers and tweaking gas tubes to have proper clearance and alignment. Most gas tubes do need a little “tweaking” to get them right – factory tubes may work OK but they typically will not function optimally without hand-fitting.
9. Gas Port Tuning: You want to avoid over-porting the gas port. Being over-gassed helps to make the gas system pressure up earlier and much more aggressively. This will cause more impulse, and increases forces and vibration affecting the most notable end along with the barrel. Tune the gas port to give the level of pressure required to function properly and adequately but you can forget.
10. Front/Back Bolt Play: If accuracy is definitely the game, don’t leave a great deal of front/back bolt play (keep it .003? but at most .005?). We’ve seen factory rifles run .012? to .015? play, that is OK if you need to leave room for dirt and grime in a military application. However, that level of play is just not ideal for a very high-accuracy AR build. A great deal of front/back bolt play allows rounds being hammered in the chamber and in reality re-formed inside a non-consistent way, since they are loaded in the chamber.
11. Component Quality: Use good parts from the reputable source and stay wary of “gun show specials”. All parts are NOT the same. Some are great, some are not so good, and some aftermarket parts are merely bad. Don’t be afraid to utilize mil-spec-type carriers; in general they are excellent for an accuracy build. Also, understand that simply because a carrier says “National Match” or anything else upon it does not necessarily mean it’s any better. Be skeptical of chrome-plated parts as being the chrome plating may change the parts dimensionally and might also allow it to be hard to do hand-fitting for fit and function.
12. Upper to reduce Fit: A good upper/lower fit helps. For quick and dirty fit enhancement, an Accu-Wedge within the rear helps a lot. The best option is to sleep the top into a specific lower to ensure the lower and upper, when together, will be more like one integral unit. For your upper receivers we produce, we try to get the specs as near as we can, yet still fit the various lowers in the marketplace place.
13. Muzzle Attachments: Don’t screw the muzzle (literally). Leave the maximum amount of metal about the barrel in the muzzle since you can. People love to thread the muzzle for the flash hider, suppressor, muzzle brake, or some other attachment, but if you really want accuracy, leave just as much metal since you can there. And, for those who have an issue that screws on, set it up to ensure that it may be put on and possess it stay there without putting a lot of torque and stress on it right in which the bullet exits the bore. If you are intending to thread the end in the barrel, make it concentric with the bore and ensure everything you screw on the website is just as well. For many muzzle attachments, also ensure that the holes through which the bullet passes through are dead true to the bore. Many aftermarket screw-on everything is not so good doing this. 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 ought to vent down equally). Uneven venting of gas can wreck accuracy.
14. Quality Ammunition: Ammo can be a whole story itself, but loads which are too hot typically shoot poorly in how to install an upper receiver. If you want 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 virtually had exactly the same features and things carried out to them as explained in this article, plus they all shot great.