AR-15s

Build a More Accurate AR-15

Black AR-15, barrel to the right on a white background

Many folks have different ideas about accuracy. Absolute accuracy is, of course, all shots in a single hole matching the diameter of the bullet.

That doesn’t happen unless you fire a single shot, although just the same, the AR-15 rifle may be an accurate platform. A few years ago, I was the proud owner of a precision, bolt-action .223 Remington-caliber rifle. With its heavy barrel and 20-power scope, the rifle was very precise. It was no mean feat to place three rounds of Federal Match into a .5-inch group at 100 yards.

Black AR-15, barrel to the right on a white background
A good AR-15 rifle is accurate and reliable. To be all it can be, the AR needs a little tweaking.

I also owned a good quality, although ordinary, 16-inch barrel AR-15 carbine. I mounted an ATN scope and discovered, the Black Rifle would do 1.5 MOA at 100 yards. Later, after acquiring a Daniel Defense rifle and stuffing the magazine with Federal Match, I discovered the rifle would group three rounds into 1-inch—not some of the time, but all of the time when I did my part.

Red AccuWedge on a white background
The simple AccuWedge is a big help in tightening the receiver.

I traded the bolt gun and never looked back. All AR-15 rifles are not created equal, and all may be improved. Some may be brought to an uncanny high level of precision.

Let’s look at where to begin.

The Receiver

The receiver is a two-piece design. The fit is not always tight and can be improved considerably. An AccuWedge is the best $4.00 you can spend. Seat the AccuWedge in the rear of the receiver behind the disassembly pin.

Adjustable Stocks

Young man in white t-shirt proofing his AR-15 with wooded area behind him
Begin with proofing the rifle; do not begin your work until the rifle is proven reliable and reasonably accurate.

We all use adjustable stocks these days, and they are great for adjusting the length of pull, although not as great for precision.

  • A true precision rifle stock is a good choice.
  • Check the lock nut on the stock. Use low-strength Loctite to tighten that part. It works well and stabilizes the stock without replacement or impeding function.
  • Another important choice is to choose a buttstock that features a flat toe. A triangular toe is less effective for prone fire and true precision fire.
Black AR-15 with focus on the Ergo Grip on a light tan background
The Ergo Grip adds to the rigidity of your firing grip.

The Grip

Precision rifles demand a consistent grip.  The standard grip is fine for most work. Some prefer it for tactical work because it is easy to slide your hand off the grip to the magazine release. For precision shooting, a standard grip leaves much to be desired. The Ergo Grip makes a world of difference.

The Handguards

The next problem is handguards. The handguard of the original rifle was two pieces. It was okay, although it really did not encourage precision shooting. I found quite a few handguards at Cheaper Than Dirt!, including free-floating models.

You may not need a quad rail for precision shooting, as it is more important to keep a comfortable grip on the rifle. Free floating not only looks good, it enhances accuracy by removing pressure that could be placed on the barrel and effecting accuracy with changes in environmental conditions or hand pressure. That is another option that looks simple and certainly is not beyond the skills of a careful and patient home hobbyist. The handguard on the rifle may or may not be precision grade, but a change should be beneficial.

The Trigger

The AR-15 trigger is pretty simple. It butts into a notch in the hammer. Press the trigger, and it moves out of the notch and the hammer flies forward. The hammer strikes the firing pin, and the rifle fires. While you press the trigger, a lot is going on.

  1. The bolt cycles and resets the hammer.
  2. The hammer returns, yet the trigger is still pressed.
  3. The hammer catches the disconnect.
  4. The trigger then moves back into the hammer as you release it.

Never file, polish or stone the trigger unless you really know what you are doing. For instance, stoning the sear is a common way gunsmiths used to, and many still may, perform a trigger job. However, given the accuracy and speed of CNC machines, you’ll get a better, more reliable outcome, by simply dropping in an after market trigger. Modifying the trigger by filing or stoning, may cause slam fires or more than one round to be fired per pull of the trigger which would create an unsafe condition and may cause you to run afoul of the law. While I have never experienced or witnessed either of those, what I have seen from a bad trigger job is pretty sad, and that is a failure to fire. The scenario played out like this. Rack the bolt, and press the trigger. The rifle fired but it did not reset. Rack the bolt, fire, press the trigger—no bang!

By far, the best thing to do is replace the AR-15 trigger with a Timney or other high-quality unit. It will be money well spent. The last Timney I installed not only went in without a problem, it also broke at 3 pounds very cleanly. I recently tested two good-quality AR-15 rifles.

  • One exhibited 6 pounds of trigger compression, which is about average.
  • The other broke at a heavy 9 pounds.

Precision shooting is not in the cards. The rub is that the rifle with the heavier trigger was my favorite and the one I would most likely fit with a match trigger. As a semi-related side note to the multi-fire per press of the trigger scenario, no matter what the cinema depicts our semi-auto AR-15 rifles do not have full-auto bolt carriers and are not thus designed for full auto. For AR’s with the capability to fire full auto, the carrier must be purpose designed for proper functioning, but are otherwise generally identical.

The Barrel

The AR-15 barrel is simple to change—just a barrel nut. The choice is between 16 or 20 inches—it almost goes without saying that you will want to choose a match-grade barrel to wring out the best accuracy. The 20-inch barrel delivers more velocity and precision both are essential to long-range success. The variations in twist and taper are endless, so the choice is yours. That is a personal choice, and unless you have a real need for a lightweight rifle, the 20-inch barrel makes a lot of sense.

Most precision shooters favor a 7-, 8- or one-turn-in 9-inch twist. The original 1:14-inch Armalite barrel turned out some RPMs, but was designed at a time when the military was using shorter and lighter bullets. Given today’s longer and heavier options, a 1:9 stabilizes anything I need to stabilize, including the wonderfully accurate Federal Gold Match 77-grain loading—a bit unusual because the 1:9 typically will stabilize up to a 75-grain bullet, but just at the edge of its effective envelope. Consider a 1:8 twist for the best all around compromise or look to the military, which uses a 1:7 with it 62-grain M855 cartridge.

The Sights

The sights are very important. Combat sights are great for combat, and precision shooting demands something more advanced. We will cover optical sights in another installment and, chances are, you will not use iron sights at all.

Two black forends for an AR-15
Look at the difference in forends—the modern version has more utility and 2 inches greater sight radius.

However, many matches and different levels of shooting demand iron sights. The Magpul MBUS rear sight gives excellent results on every rail gun I own, but is designed as a combat sight and normally employed when the primary optic fails. Instead look for offerings such as Armalite’s National Match sights and components.

Remember, a tiny fraction of movement can result in a one-inch miss at 300 yards. You may want to properly sight in the front sight, leave it in place and then Loctite it there.

Ammunition

I’ll leave you with a final note on ammunition selection.

  • Burner-grade, steel-case ammunition is okay for practice, but never gives stellar accuracy.
  • Federal Gold Match and very few other loads will serve well for precision shooting.
  • Federal American Eagle FMJ loads are accurate enough for meaningful practice
  • You should handload for optimum results. However, match-grade loads and monolithic designs will carry the day for most.

So what have you done to make your AR-15 the precision gun of your dreams? Tell us all about it in the comment section.

[bob]

About the Author:

Bob Campbell

Bob Campbell’s primary qualification is a lifelong love of firearms, writing, and scholarship. He holds a degree in Criminal Justice but is an autodidact in matters important to his readers. Campbell considers unarmed skills the first line of defense and the handgun the last resort. (He gets it honest- his uncle Jerry Campbell is in the Boxer’s Hall of Fame.)

Campbell has authored well over 6,000 articles columns and reviews and fourteen books for major publishers including Gun Digest, Skyhorse and Paladin Press. Campbell served as a peace officer and security professional and has made hundreds of arrests and been injured on the job more than once.

He has written curriculum on the university level, served as a lead missionary, and is desperately in love with Joyce. He is training his grandchildren not to be snowflakes. At an age when many are thinking of retirement, Bob is working a 60-hour week and awaits being taken up in a whirlwind many years in the future.


Published in
Black Belt Magazine
Combat Handguns
Handloader
Rifle Magazine
Handguns
Gun Digest
Gun World
Tactical World
SWAT Magazine
American Gunsmith
Gun Tests Magazine
Women and Guns
The Journal Voice of American Law Enforcement
Police Magazine
Law Enforcement Technology
The Firearms Instructor
Tactical World
Concealed Carry Magazine
Concealed Carry Handguns



Books published

Holsters for Combat and Concealed Carry
The 1911 Automatic Pistol
The Handgun in Personal Defense
The Illustrated Guide to Handgun Skills
The Hunter and the Hunted
The Gun Digest Book of Personal Defense
The Gun Digest Book of the 1911
The Gun Digest Book of the 1911 second edition
Dealing with the Great Ammunition Shortage
Commando Gunsmithing
The Ultimate Book of Gunfighting
Preppers Guide to Rifles
Preppers Guide to Shotguns
The Accurate Handgun
The Mission of Cheaper Than Dirt!'s blog, The Shooter's Log, is to provide information—not opinions—to our customers and the shooting community. We want you, our readers, to be able to make informed decisions. The information provided here does not represent the views of Cheaper Than Dirt!

Comments (39)

  1. I built a 6.5 Grendel 24″ 1/8 twist giesele 2 stage free-floating handguard PRS stock vortex viper 6.5-20×50 scope. Shoots 1/2 moa with Wolf Gold Dot 140gr

  2. I’m really glad i found this page.
    You are doing something ive tried to do.
    Have a buis UNDER my scope.

    I have both the P223 and a Buckmaster 3×9. I have a magpul knock off that is just a bit too tall and hits the eye piece. I have the high UTG LE QD rings. They are great and the knock off sight is as well.
    I just have to pull the sights off to use the scope.

    what rings are you using and the height from top of rail to bottom of saddle?

    Thanks for some great articles! Having a blast with my first AR.

  3. Your very first recommendation is to install an Accuwedge, which does absolutely nothing to improve the accuracy of an AR rifle. I stopped reading right there.

    1. The purpose of the accuwedge is to take up slack between the upper and lower receiver. While it does nothing to increase the mechanical precision of the rifle, it does increase accuracy by allowing minor variance in grip pressure and angel to not shift the mated surfaces between the upper and lower. A good example of this would be to take an AR with a really poor fit between the upper and lower. Fire a group right handed while really cranking down on the foreend and grip. Squeeze it in tight until nothing is rattling. Zero your rifle for that group. Now shoot it left handed, doing the same thing. You’ll be putting torque on the upper and lower in opposite directions and your zero will be gone.

      If you already have an upper and a lower that fit together with absolutely zero movement, good for you. If you don’t, an accuwedge will absolutely make your shooting more consistent. That is of course assuming you’re a good enough shot to see the diference.

  4. Lots of good info guys. Thanks for the post. I especially like the free floating comment in the third paragraph. Not everyone realizes how this helps accuracy: letting the barrel do it’s thing naturally after firing a round.

  5. I bought a Windom Weaponry SRC, changed out the trigger with Geisselle SSA-E , MI -SS12G2 forend, Harris Bipod,G-27 hand grip, Aimpoint Patrol Red Dot, Troy Iron battle sights, Troy 3 piece forward hand grip and its been a great shooter

  6. Accuracy is the proximity of measurement results to the true value; precision, the repeatability, or reproducibility of the measurement

  7. You forgot one of the cheapest and easiest pieces to swap out to aid in accuracy… Swap out your gas block for an adjustable gas block so you can dial your AR in for the cartridge that you plan on using. This will help in reducing recoil.

  8. I’m curious to know what the AR is in the photo at the beginning of this article, the one with the SS barrel. I’m guessing it is a custom build.

  9. Pingback: Top 10 AR-15 Posts
  10. “As a semi-related side note to the multi-fire per press of the trigger scenario, no matter what the cinema depicts our semi-auto AR-15 rifles do not have full-auto bolt carriers and are not thus designed for full auto.”
    My semi auto AR has a full auto bolt carrier. The presence of a full auto bolt carrier does not make a gun full auto, and a full auto gun would still fire in full auto with a semi auto carrier. The full auto carrier is stouter to survive the higher abuse of full auto, and has slightly different geometry to protect the firing pin and hammer from damage during high rates of fire. Most top grade AR manufacturers use full auto carriers in their semi auto guns.

    1. The M16 requires and M16 bolt carrier and will not fire full auto if fitted with an AR15 carrier.

  11. I carried an M16 A2 in Nam and have had a handful of ARs over the past 30-40 years both off-the-shelf and user-assembled. I gleaned a lot of ‘pearls’ from this article and look forwar to more. Thanks.

    1. I think you meant the M16-A1 in Nam! The M16A1 was the finalized production model in 1967.
      The Marines were the first branch of the U.S. Armed Forces to adopt the M16A2 in the early/mid-1980s, with the United States Army following suit in the late 1980s.

    2. I first issued my M16A2 in Mid 86. I didn’t like the 3 round burst. I preferred to control the rate of fire with my finger. I could squeeze a single round in full auto, and that was with my fox hole buddy pelting me with his brass. I hate it when it hit the back of your neck. It kinda burns. :o)

  12. Shooting a Bushmaster XM-15 with the factory 20″ 1-in-9, chrome-lined barrel with 5,000 rounds through it, Jewel Trigger, free floating barrel, Leupold VX-3, hand-loaded 68gr Hornady Match HPBT ammo that was tuned for the rifle, I can easily get 0.7″ 10-shot groups…and I am a terrible shot.

    I’ve tried hand-loading 75-gr A-Max and that bullet just will not stabilize. At 600 yards I get impacts in the dirt below the target, then a shot high right, then low left… I just can’t get them to shoot strait.

    One thing I’ve noticed is, AR’s don’t seem to like hot loads. I load the 68 grain bullets to, approximately, 2700 ft/sec using Varget. Other high-power competitors have the same experience: 68/69 grain bullet around 2600-2700 ft/sec shoots best.

    I’ve tried every “match-grade factory ammo I could find and none shoot well. The recoil and report from those loads are all more intense than my hand-loads so I’m concluding they are loaded hotter than my hand-loads.

    For factory ammo, Winchester USA (white box) ammo works best for me. We even have some NRA Service Rifle guys who shoot it in competition and they do well with it…at 100-200 yards.

    I’m curious if other people here have similar experience with 75gr A-Max and with noticing that “hotter” loads do not work well in AR’s.

    1. I agree. My rifle doesnt like top end loads either.
      “hottest” load i have is 55gr varmageddens on 24gr of H335 and cci 450 primers. .335″ at 50 yds.

      Faster they go, the less accurate. Just gotta find that perfect harmonic.

  13. The comment in the article that refers to the Armalite 1-14 barrel turning out some RPM’s, is technically inaccurate, if you are referring to “revolutions per minute” of the bullet. By modern standards, 1-14 is a very slow twist rate.
    If you were referring to “rounds per minute” – cyclic rate – you would be correct.

  14. The above replacement parts for making your AR shoot more accurate sounds pretty good, but I’ve got a “bone stock” Heavy Barrel Bushmaster made in Maine when owned by Remington that will shoot under 3/4″ with a $50 Tasco scope all day long! I am shooting had loads, but they are not tailor made for this gun. I think I’ll leave it as it is….

    1. Yeah, but are you doing that at 100 yds. or 500 yds. plus? The article is about building a “Precision” AR-15, 3/4″ groups won’t win you any matches. If you are happy with your 3/4″ groups than more power to you, but just imagine how tighter your groups would be if you followed the suggestions of the author 🙂 🙂

  15. I have a Bushmaster Varminter, which is a DCM match rifle with a flattop, and 24″ heavy free-floated, fluted barrel w/1:9 twist. Some call them “Space Guns” in competition. It has the Bushmaster 2-stage competition trigger, matched bolt and chamber (not chromed so it has tighter tolerances). On top it carries a Leupold VXII 6-18x40mm with target turrets. It was broken in as recommended for best accuracy and has never been over-heated. I hand-load 60 grain Hornady V-max to a MV of 3100 fps. It shoots many through the same hole at 100 yds off the bench and virtually all 5-shot groups are less than 1/2 inch with a best group of six shots into .29 inches. If you want real accuracy off the shelf, buy a top-of-the-line gun (they’re not cheap) with all of the above, break it in correctly (don’t run it as fast as it will fire) and be really anal with your hand loads. I’ve only shot it out to 200 yds but it maintains .5 MOA at 200. I don’t shoot any organized competition but, at 70 years old, with this set-up, I’m really happy.

    1. Nice post Labman. I have a similar setup utilizing a Rock River A4 Varmint Rifle also with a 24″ (heavy match SS) barrel. Would you please describe your “break-in” process for the barrel you mention. RRA (I talked to BJ Blick, RRA factory gunsmith), maintains that their barrels are hand-lapped and do NOT require “break-in”. Any details or insight you have is appreciated. Have yet to fire the rifle so any advice conducive to ensuring a very accurate rifle is paramount.

      Best regards,

      Mike

  16. While I like your idea of how to build an accurate AR-15, why not tell us how to do it in New York. They do not allow pistol grips or adjustable stocks here. Any suqestions??

  17. I bought a Del-Ton 20″ Rifle. Looks like the M16 rifle issued to troops. Took that rifle and dropped in a Timney trigger, took the for end off and installed a lighter, more ergonomic for end, replaced the front sight gas block with a low mount gas block and put a JP full length stock on the end. The iron sights are gone and in their place is a Nikon P223 scope.

    This gun has a factory Del-Ton barrel, just a carbon steel barrel, nothing fancy and it will shoot an inch or smaller groups at 100 yards, oh yes, I put one of those rubber things that takes the slop out of the upper and lower receiver. I’m not going to tell my load because I don’t want other people trying it, needless to say it’s over the book loading but it’s much more accurate than anything I found in loading manuals. I’ll just say I’m using a 55 grain Barnes Hollow Point. Haven’t even tried the heavier bullets.

  18. I got lucky with my first AR build. I started out with an 80% glass filled polymer lower that I hand milled with my Dremmel and I was able to locate an upper with a 1 in 8 barell made by FN. I put a Palmetto State armory BCG inside the upper receiver and a Blackhawk! trigger group. Palmetto State Armory had a Bushnell 1-4X24 tactical scope mounted in a Burris hard base for an excellent price. I found a nice quad rail, put some rail covers on it and mounted a tango down with a bi-pod that pops out the bottom of it. The stock is a six position by UTG and I have a single point sling by Bulldog . I located a small lot of Magpul 30 round mags. I’m using the stock combat sights with the detachable carry handle installed and an adapter on top for the scope. The only thing I haven’t decided on yet is laser and light! I’ve put a couple boxes of Federal through it and it functions flawlessly. Zombies anyone?

  19. First time I’ve heard about the accu-wedge. I’m new to the AR-15 and I just recently bought an Adams Arms blemished carbine. The main complaint I have with it is that it feels like it wobbles. I think the accu-wedge might just be the ticket. I’m gonna look for one right away.

    1. The Accu-Wedge will definitely help your cause. I also added shims to my front takedown pin from this company, they come in various thicknesses…

      http://michigancenteroutdoors.com/ar_15_shims.html

      Also, a lot of the higher end lower manufacturers are starting to add a upper receiver tensioning set screw under the grip. It does the same thing as the Accu-Wedge but better. I am doing a new build with a Seekins Precision lower and I tell you what, it makes all the difference in the world. Also they have replaced a lot of the roll pins with allen head screw in pins that make life a whole lot easier.

      http://www.seekinsprecision.com/parts-and-accessories/ar-lowers.html

  20. I am currently building a 6.8 SPC hunting AR. Although, I did not choose a match grade barrel, it is 20″, 416 Stainless, fluted and heavy. My trigger selection is a RRA National Match with JP Enterprises 3.5# springs. It will employ a rifle length free-float handguard that will cover the low-pro intermediate gas system. I selected a Hogue grip and Magpul MOE rifle stock for fixed length reliability. An AccuWedge will also be installed. Optics on top will be the Burris C4.

    If this rifle isn’t accurate, I will be owning the blame.

  21. All good mods which I gave on most of my ARs, but we can’t forget the most basic component of accuracy, the shooter. The best modifications you can make for accuracy of any weapon is practice with proper technique and professional instruction if able, as most guns off the shelf these days are more accurate than the average shooter

  22. I bought a Rock River NM and it shoots way better than I do. The RR is suppose to be the best Out of the box shooter going.vvI do need to put an AccuWedge into it and I did put a Micro sight on it. I pretend I am a match shooter and at 66 yrs young the sight made all the difference in the world and is legal at the National Matches. I highly recommend it if you have trouble seeing the post.

    1. National Match rifle, maybe… As for the best “out of the box” shooter, that is highly debatable…

      The RR NM is not a stock AR, it is a custom rifle. It already has a bunch of upgrades that come with it… Free floated handguard, heavy SS cryogenically treated match grade barrel, 2 stage match trigger, RRA chrome BCG and to top it all off it is chambered in .223 Wylde. So if you want to talk best “out of the box” non-stock rifles, the list is many…

      1. JP Enterprises – CTR-02, SCR-11, PSC-11 (Pretty much any one of their rifles)
      2. Noveske – Any one of their rifles
      3. LWRC International – Any of their rifles
      4. Seekins – Any of their rifles
      5. Patriot Ordinance Factory – Any of their rifles
      6. Larue Tactical – Any of their rifles
      7. Christensen Arms – Any of their rifles
      8. etc…..

      To many to choose from, it all comes down to how much you want to spend on a “Stock” AR. With AR’s “out of the box” is a very loose term.

  23. I recently put together my first parts kit to be my first ar platform. Although I haven changed many of the internals for accuracy, I did put in a BCM Gunfighter charging handle(mod 1). It had a slightly larger latch that allows for easier one handed manipulation of the charging handle with a scope mounted. I also installed and magpul K-2 grip, the original felt terrible were the K-2 has almost a 1911 feel to it. I can get 2 moa at 100 yrds with a fixed 3x scope. Thanks for the tips, I’ll probably free float the barrel in the near future.

  24. In July 2013, Colt released the AR15A4. It took me until March 2014 to be able to locate one for purchase, which I then did. This is the Colt civilian version of what a Marine rifleman is issued. That’s it! No big story, no extra expense or fanciful embellishments. Stock rifle with 20+ years of military experience trusting my life and that of my buddies to this weapons platform. I also own 3 Colt LE6920 models in varying configurations. I have done nothing to those either. Why mess with what works? I also own a Bushmaster XM15 patrolman A2 with a rail system, bungie sling, USGI rubber butt stock pad, Magwell grip and
    bi-pod add-ons. Haven’t tweaked any internals, though. Just personalized it some. Again, why change what works? Simply put, I would trust my life to this Bushmaster, too.

    1. You are right, the platform is a great starting point. But like most things in life, there are enhancements that can greatly improve on it. And the enhanced rifles are just as reliable as the originals and more accurate. I built my first AR using an American Spirit Arms lower back in 2000 using a bunch of non stock parts and the rifle has never failed me. I’m now building an AR using a Seekins Precision upper and lower and I am sure it will be just as reliable but even more accurate than any of the factory Colts.

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