Accuracy of the Milspec AR15 Carbine barrel


This post is a short follow up to my recent project/ article to shooting the AR15 at 1,000 yards.   The point of the long range shoot was to show that the system is not the short range gun that a lot of people who know every little, claim it to be.   I talked about making effective hits on a man sized target more then accuracy the last time, so this time I am going to talk a bit about accuracy of a carbine that does not have a match barrel or trigger in it


Above is a picture you can click on to make larger.  It is several groups shot from a M4 carbine at 200 yards.  The aiming points are the orange dots that are 1 inch in diameter.   While I did not use a match barrel or trigger, I did use a Leupold 18x target scope to be able to  see well enough.  I also shot from a bench using a rest adn sand bags and all the proper technique used during a BR match.  OF course, I also used match ammo for the testing.    The typical carbine of good quality, even with a milspec chromed lined barrel with NATO chamber will deliver accuracy at a level not really needed from a military or defensive carbine.      I used a few different types of match ammo during testing. All of it heavy. All of my carbines use the 1/7 twist so I can take advantage of the better ammo.

From time to time you will read some guy on a gun board telling you how his carbine or rifle will shoot M193 or M855 into sub MOA groups.   This means they shot 5 or 10 or whatever, rounds, into a group smaller then 1 inch at 100 yards, or 2 inches at 200 yards etc.   This is so close to impossible, you can safely call them a  liar.  The gun may be very accurate, the barrel may even be the finest match barrel money can buy with a jewel trigger . But the quality of the gun, can not over come, the quality of the ammo.   The fact is,  loaded rounds have to be made under very strict and demanding quality control processes to be consistent.  That is how the bullets group so close.  Having a good gun, and good ammo as well as proper skill all go together. But, you can not have a great gun, and perfect skill and shoot sub minute of angle with ammo the factory that made it only needed it to be 4 MOA.   Nothing you or the gun can do, will over come this. It is a universal fact.  Now, some fluke ammo lots can shoot good. It is not that military ammo can not be made to shoot well, it can, but it needs a level of care that the factoriues making it do not intend to give, or the gov even needs. It takes more time, and components made to very high standard.   Why would lake city make M855 that would shoot 1/4 inch at 10 yards? So it can be fired form a  SAW  at a window in a mud hut 567 yards away ?   No. Just no.   If you want to shoot tight groups ( 1 MOA or less) with your gun, you have to have good ammo along with everything else.


The above picture has been shown before on this blog.  It is 18 shots fired into one group, from a milspec barrel Colt 6940, I used the same methods as when I fired the groups above.   I fired this group to bust the very common myth that a 1/7 twist has to shoot bullets that weigh more then 62 grains.

Those 18 rounds are 40 grain Hornaday ballistic tip bullets. That orange dot is once again, A 1 inch dot.   The 1/7 twist barrel will shoot lighter bullets just fine. That is, if it is a well made barrel to begin with, not a match barrel. Not some noveske match barrel, but a milspec chrome lined barrel.  How much more accuracy  do you need? Is it worth the extra cost?   I am always amused to see some of the barrels people buy, and the privce of these barrels. just to blas M193 or wolf ammo into a target 25 to 50 yards away, or even 100 yards.   Ask yourself how much you gained from that highly expensive barrel with some new gee wiz coating, and was it really worth it.  Really test you current barrel with good ammo before you start buying some of the hyped “match barrel”  USe a good scope and ammo and BR technique, or get some who knows how, and test what you already got.  You may be very surprised.







Above is another example. This was using a popular and  common load used during high power for the AR15. It  is the Seirra 77 grain bullet that I loaded myself with the utmost care. It is 20 rounds.   This is not a special barrel. I have seen many plain milspec barrels that would do at the worst 1 to 2 MOA  with decent ammo, and usually it is closer to 1.5 MOA with match ammo.    AR15 pattern carbines and their accuracy is like a diamond in the rough. You have to learn to work around the things that hold you back. The trigger on a milspec rack grade gun is not pleasant or easy to use when shooting for small groups, but you can get used to it and learn it.  The barrels are not always free floated, but you can shoot in ways to not stress the barrel and get it to hot. Optics can be changed around easily and the butt stocks can be worked around. It is almost a mental block, or conditioning that has people thinking that their rack grade guns have to be upgraded to shoot well.  Of course there are some crap guns out there made by more then a few crap factories, but even the most unreliable will often have pretty decent barrels.  It is hard to mess up a AR15 when it comes to accuracy, there is very little that can effect it once the barrel is floated , and even if its not, it is already very close to being free floated.  The thing to remember though, is that accuracy is not everything.. You must have a carbine or rifle that is 100 percent reliable and combat hardened if you want it for defense use.  If you are a dirt blaster or can shooter, then it does not matter I guess.  If you want tight groups, the most import thing to remember after your own skill, and quality of the barrel is that you have to have quality ammo.  Never use M193 or M855 or any ammo that is not meant to be match accurate, as a way to judge your rifles potential accuracy.


  1. Excellent article. This has been what I value in LR articles. Straight talk, no mumbo jumbo. I’m amazed like you said how people buy into a sales pitch for their weapon. People that want the magical rifle that can shoot 2000+ yards but at a “cheap” price and a they put a big 5 scope on it.
    Again an excellent read.

    • thanks man. I try to help people understand that a lot of what is talked about is more marketing hype then people believe. Our rifles are a lot better then people thinks. But if people find out, it wont sell many 3500 dollar special addition super cool instructor rifles

    • Hey-what’s wrong with “Big 5???!”( well other than low quality, made in ” China ” crap)

      But yeah, Barska and Tasco scopes aren’t gonna’ make that magic 500 yd plus shot and “x”

  2. Upgrades to skill should always come before accessories. With practice comes the need for quality ammunition. One of the best things a shooter can do is practice frequently and reloading makes that possible to do with excellent quality ammunition. I have never come in first place, but at my first local competition with an iron sighted rifle I managed to out-shoot a few people with fancy M4s.

    Knowing what you can do with your rifle as well as establishing a baseline standard for yourself is a benefit of practice and competition.

  3. Great read! Since I have not participated in a bench rest, nor know anybody around here who does it, what are the proper techniques you are talking about? I’d be curious to see what some of my rifles/carbines can do using these techniques and quality ammo.

  4. Another good no nonsense piece, thanks. I’ve always thought alot of gimmicks and hype were in the AR markets, especially after seeing what a good base rifle is capable of.

  5. I have a standard Colt M4 AR-15 LE6920 in 5.56mm caliber 16 inch barrel. Can I convert this to a 1 in 7 twist 20″ Milspec barrel from Colt?

    • yeah, but why would you want to? you wont really gain anything, or be able to do anything the M4 wont already do.
      and colt ,makes the AR15A4 model., which is a 20 inch rifle with 1/7 twist just like the M16A4 used by the USMC and US ARMY.. they been making and selling them for about two years now

  6. Wrong- there are some CL issue weapons that can shoot 3/4 MOA and Ive seen them. This is not with M855 but with quality ammunition. Every rifle is different, sometimes an issue rifle can shoot very well. This is coming from a 10 yr infantry SSG. Most issue carbines and rifles average about 2-3 MOA with M855. Ive seen some shoot much better, especially with match grade ammunition. So to say that anyone who claims otherwise, in your little blog here, is a “liar”, youre wrong. Dead wrong.

    • should have spent 10 years learning how to better read. I never said CL issued weapons would not shoot sub minute. especially since I demonstrated such in the damn article. what I said was. people who say they can take low quality military ball and shoot sub MOA are lying. a rifle can not shoot low quality no matter how perfect the rifle and barrel may be made. its is simply impossible on a side note. having military service does not get your instant cred and make you an impeccable man of honest and subject matter expert here in our opinion. and we are veterans LEO and DHS among other things with experience. and none of those jobs and title mean shit by themselves. as a general rule to any reader. saying you used to be are are current military does not get you extra clout with your opinion with us. we have seen many 20-30 military who are just as full of shit as anyone else. competency in one thing does not equal everything. and the mil love to pass on info they heard from some one else, even though they have no idea if its true or not , not singling you out Chris. just generally speaking to anyone who starts an argument with how wrong we are because ” i was an infantry/combat/20 year vet etv etc” My Dad was in the Army for years and used a AR15 in Vietnam and still swears it was made by Mattel.

      • Got to agree with the SSG…. Just last Saturday I fed pmc xtac m855 green tip into my ar that has no two parts from the same company except the irons and achieved very close to minute of angle. While I was in the army I was never able to fire my issued weapon at paper at any greater distance than the 25 yard zero target. We qualified on pop up ranges; however I did plant a 500m shot on an AAF with my m4 utilizing the 600m mark on my acog and it landed exactly where I thought it would. Ole SSG has more street cred in my eyes than you ever will; but I’m nobody special.

        • ole SSG can tell you whatever bullshit he wants and you can buy it if you want. by MIL STD tech sheet and official TDPs of the ammo says otherwise. no one said you cant hit man sized targets at range with M855. and “close to MOA” is not MOA or SUB MOA, and military service does not equal instant expertise and cred with us here just by virtue of being in the military. Ole SSG may have spent 20 years in the military but I bet he has spent 0 amount of that time doing technical testing of dozens of rounds over those years . Lastly. if you like what SSG has to say, then may I suggest you go find ole SSGs website and read about his claims instead of us. That way your mind won’t be troubled by facts and real data decades old

  7. Very true and not often talked about. so a very good article. I put a AR15 almost exactly spec to the Nam issue one I knew. 20 Inch BBL. Made for the M193. If I shoot load I worked up for this rifle and have a rest I can hit the kill zone of a man sized target at 300 yards no effort, 400 yards is bit more dicey but the round always hits somewhere on the silhouette.What more would I ever need? I am using the iron sights, no scope.I am older and not the shjot I was 40 years ago but even with Mosin Nagant (7,62 X 54 MM R) with iron sights I can hit a man sized target at 250 yards almost every time.with occasional flyers. You are definitely right that all 3 must be there for MOA or rare Sub moa shoot 1) Rifle quality (2 shooting skill and 3) quality Ammo mainly best is hand loads for your particular gun. If any one is lacking you might shoot MOa but not so often and sub moa like you say not really possible.

  8. This article is one of the best written here. My current rifle is a RRA predator pursuit. It is literally a 1/2 MOA rifle bagged and benched with hand loads.

    I have embarked on a second rifle and this one is going to be a “world has gone to hell” rifle. I won’t bore you with the parts list but the heart of this rifle will be a chrome lined, 20 inch, 7 twist, Chrome molly Vanadium barrel . I’ll bet your my beer money If I get my barrel from a quality source
    ( I’m looking at you FN) I can get it to shoot an honest minute with a good 77 grain hand load.

    • thank for the kind words, Its not my favorite article. that would be my article about shooting the AR15 at 1000 yards. But it was the article I felt needed to be written to dispel some ignorant myths about GI barrels

  9. Hello Shawn,
    super article! I have a put together from cheap (but in-spec) parts with a $100.00 stainless barrel and after working up a good load with bullet seated at 8 thousandths of the lands will hover around 1/2 MOA at 100 yds..

  10. I think people often have too high expectations. I usually shoot a 4 inch group with my AR’s at 110 yds (100m) from a bench rest. They will sometimes open up to 6 inches. I use 9x scope. I mostly shoot cheap Tulammo. I also shoot Remington and Federal. The better ammo usually shoots a 1 inch smaller group.

    I recommend Dry fire exercises before and after. If your crosshairs stay on the target when you squeeze the trigger, you are doing fine.

  11. I know this is a carbine article, but I have an AR-15 with a BCM 20 inch, 7 twist, chrome lined, Gov. profile barrel. With home rolled 77 grain ammo it shoots tighter than most people can hold. It will consistently group under and inch from the 100 yards bench. I don’t know enough to say this is typical of BCM barrels or I got a ringer but its a keeper for sure.

    • despite a lot of claims online a hammer forged barrel, will not shoot as well as other. It will keep the accuracy it was “born with” longer, but usually they just don’t have that edge. A milspec quality barrel for a carbine with handloads will do or come close to the results you are getting. BCM is pretty well known for making pretty good barrels. I have no experiences with accuracy testing any BCM barrels first hand myself

  12. Interesting read!

    I actually read an old military specification for the M855 Ball (MIL-C-63989C) just minutes before finding your article. The specification actually mentions (page 5, point 3.11) the accuracy demanded out of M855 Ball. It is given as either 6.8 inches at 600 yards, or 1.8 inches at 200 yards. That would be about 1.1-0.9 MOA. Those numbers where actually news to me. Where did you find your numbers, about 4 MOA?

    The standard can be found here: You wan’t to use the orange download button, the rest are hidden adds.

    There is actually another specification for the AR15 in it self. It also mentions the precision of the ammo used for testing rifle. That ammunition, also standard M855 ball, is cited as 3,4-4 inches at 600 yards. I have no clue as to why the rifle specification prints out another accuracy than the actually ammo specification that it is citing, but it might just be an error. And those 4 inches might also be where the idea of M855 beeing 4 MOA might wrongly come from.

    What is your take on all this? I am not trying to pick a fight, just finding out about the actual accuracy of M855 ammo =)

    • I don’t even remember where I got that from now, its been so long. I did a quick googles search and found some reference for M855 numbers at the time to jot something down for the post. I may as well have just made it up, the point was not really to lecture on the specs but to show what it can do and what the service carbine could do beyond “common knowledge.” I may have posted the acceptable group size at the large end of the minimum standards it has to meet to make a point. I can’t really offer up much of a take on the info you are providing. I shoot it and what I observe with my own eyes is what I go buy. Military ammo can be extreme from great to shit from lot to lot, and claims from online expurts and vets can vary from absurd to even more absurd. my policy is to test it out myself and more often that not quality real milspec ammo shoots better than many believe. Since they all base their opinion their own often pitiful ( not an insult, just reality) marksmanship. If you like M855 and it meet your needs I encourage you to stick to it.

      • Re-found my old link to this article today so I didn’t see your reply until now. But thanks for taking the time to answer me even though I resurrected such an old article =)

        And I agree about good mil spec ammunition being really good! If I read the old specs correctly the ammo actually has a tighter spec than the AR15:s, so louse accuracy is probably more due to well used rifles (and riflemen) 😛

  13. Normally people tune ammo to match barrel harmonics. However it is possible to tune a barrel to match the ammo. What generally makes m193 ammo inaccurate is that it is a poor match for the harmonics of standard barrels. Tuning barrel harmonics in principle is the equivalent of changing the note a guitar string plays by where it is fretted. Free floated barrels are resonant structures and can be tuned enough to make even m193 ammo pretty accurate. Tuning the barrel is something which is done in Europe in match shooting – but it is pretty much a lost/unknown art in the US. The Mosin Nagant – for example – had a barrel tuned by a carefully positioned spring loaded set screw which enabled it to fire the poorly made Russian military ammo of the 1890’s quite accurately. Machine made 21st century m193 is certainly better made than that 19th century Russian ammo. I would be very careful before I would throw around terms like “impossible” or call people liars; they might have tuned their barrel harmonics enough to get m193 to shoot quite accurately. There is a video on YouTube by an old time Marine Corp match armorer on how to tune AR barrel harmonics.

    • that is a lot of typing to be saying essentially nonsense or guncounter bullshit

      You can’t “tune a barrel ” to make M193 shoot better. accuracy of ammo or barrel requires consistency. military ammo, M193 included can’t shoot accurately unless it is produced to a high standard of consistency. you are not going to shoot ammo accurately if out of 10 rounds. there may be as much as 3 grains difference in bullet weight from one extreme to the other. Or a jackets that are never close to equal thickness and balance or length Brass that is considerably thicker on one side of the neck than the other and powder charges that don’t deliver steady muzzle velocity or primers that do not burn for the same heat and length or time, every time
      military spec M193 is not match ammo, anyone who claims sub MOA constantly with it because they are so good or their guns is just so perfect, is as full of shit as a pet racoon
      the most perfectly made and tuned rifle in the world WILL NOT SHOOT POOR AMMO TO MATCH LEVELS.

  14. The only pertinent question is whether the inaccuracy of M193 is due to defects in manufacturing the ammo or whether it is a design problem due to a poor match of the ammo with the harmonics of the barrel.

    If you attempt to create match grade M193 rounds – using the best 55 grain bullets you can buy – sorted by weight – with the best brass you can get – all hand selected – with bench rest primers and powder measured to 1/100th grain etc. – all loaded to M193 velocity specifications you will discover that most of the inaccuracy problems are not manufacturing defects but harmonic problems with AR barrels. You won’t be able to do much better than M193 does.

    The M193 bullets arrive at the muzzle when the muzzle is in a high vibration state and that is what causes the bullets to spray as much as they do. None of the precision in hand loading does any good – at all – if the bullets arrive at the muzzle at the wrong time.

    M193 is sloppily built because the manufacturers know it makes very little difference in the basic accuracy of the round – which is governed by its harmonic problems.

    Read up on Chris Long’s Optimal Barrel Length theory to understand what causes these sort of harmonic problems.

    • that is just blatantly untrue. match versions of M193 have been made ,and shoot significantly better than government made m193 ammo that only has to meet a spec of 3 or 4 MOA. Last time I was at a BR match I didnt see anyone using wolf ammo and just saying ” oh well it doesnt matter, its my barrel harmonics I just had to adjust” I’m sure some guy’s theory has convinced you otherwise for some reason, maybe he’s your brother or you work for him I don’t know or care, but its out of touch with reality and known facts.

      no offense man but you are typing non-sense and I will be honest with you, this is a real world technical website. If you continue to post any more of this stuff Im gonna just delete it or block it. so if you want to argue with some one about it, go over to arfcom or m4 net and start a thread or whatever. cause this conversation is done here.


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