Accuracy Testing A Rack Grade M4 ,What Can You Expect



When I browse the gun boards on the internet, I still see the claims by bench rest experts about how a carbine has to have the barrel free floated, preferably with a 400 dollar match stainless steel barrel. Or even more laughable. with a  cold hammer forged barrel.  Otherwise you are gonna be stuck with a 4 MOA or worse, gun.  Last year I took a rack M4 out to 1,000 yards on a man sized target to show it could be done, but that was not the same as setting down from a rest and squeezing all the accuracy out of it I could get for pure precision.

So today I took a 6920 Colt ( M4) and slapped on my trusty Leupold 18x target scope, and grabbed some ammo to do some accuracy testing.   The only thing different about this gun, is it has the SSA trigger to help with the groups and a Gunfighter Charging handle along with a standard Colt ambi safety that has no effect on its barrels accuracy.  The gun still had the side sling swivel, and I even left a sling attached, and the factory hand guards.  Other than the trigger and scope to help on my end, the gun had no other upgrades to the barrel. It was as it comes from Hartford. Gun was fired from a bench with front and rear bags using the Leupold 18x target scope I use for accuracy testing.


I drew a few dots and set the target out at 100 yards and got to work. Above is a 18 round group fired with M855.  It is not a bad groups actually if you look at it in context. Some of the rounds obviously were not consistent with the rest, but the rest did give a group not bad at all for military ammo.  I have seen M855 do better, but it is not match ammo.


Then I moved to shooting match quality ammo.  The first group on the left, is 5 rounds of MK262 ammo, This is 77 grain Sierra  HPBT’s. I only fired five rounds, because that’s about all I have left. I find this to be a normal group for MK262 though.  Middle group is the Hornady TAP ammo, in .223 pressure loading, not the 556 NATO version. This is a ten round group.  And it is normal in my experience with TAP. It is pretty good stuff but not as great and super accurate as a lot of people think. But it is nothing to sneer at by any means. Its terminal performance makes it an excellent round, especially if you get the 556 pressure stuff.   Last group on right is Norma Match ammo I recently started buying and testing.  Man! I did not expect to see this group. I knew it was good stuff because I knock crows out of trees at 200 yards with it all the time in a target AR15, but this was the first time I had shot it in a carbine for accuracy. I fired ten rounds of the Norma Match. It uses the same Sierra bullet as the MK262, but obviously more care goes into the making of this ammo. Norma has long been known for super high quality brass, so it should surprise no one that any ammo they make would be outstanding.

There have been probably a  million accuracy tests of carbines on the web over the years, but it is always worth repeating since few actually put in the real effort to see what I plain rack grade barrel will do.  You can do very good work with a factory carbine despite what you will read from internet experts, and the companies trying to sell you something.  Your skill and practice are much more important than a FF tube when the gun is quality to start with.   It is important to realize that rack grade does not mean just any Ar brand that looks like a plain M4 though. There is more to making a quality gun than just looking the same as another. But a proper made gun, made to last and be tough, will offer up enough accuracy for just about anyone if they dedicate themselves to becoming a real marksman, and not just a dirt clod blaster who burns up 15 rounds a second from 15 feet.



  1. Reblogged this on The Everyday Marksman and commented:
    Shawn at loose rounds does another good article about accuracy from standard barrels. These are the kinds of articles I wish more people had access to instead of reading message board “facts.”

  2. But, but, but…. Don’t you need a 3,000 dollar AR for rapid fire at 2-10 yards. The gun magazine articles seem to think so.

  3. Excellent! I have found that investing in a quality barrel, ammo, optic, and trigger, in that order, and then working on shooting skills is the means to producing marksmanship. Money spent on further upgrades is wasted until those basic elements are mastered. If I can ask, what was your rate of fire, and where on the handguards did you place the front bag?

    • center of the HG for the bag, it runs about the full length. I have no idea what my rate of fire was, but it usually takes me about 10 minutes to fire a 5 round group when I am trying to determine a milspec barrels accuracy. I disagree with you on your order of what to get to upgrade a rifle. I feel the first and most important thing is to make sure the gun is a quality well known mfg made to spec. and high quality ammo. there is no need to buy a SS match barrel. or any of the so calle dmatch barrels for an Ar15 when you are starting. almost all Colt milspec factory barrels are more capable than the shooter with proper ammo anyway. and any trigger can be learned and worked with. A new shooter had no idea what a good trigger should feel like anyway. optics can wait as well. until you have skill. you will shoot just as mediocre with the best optic as you will with irons. Solid gun, good ammo ( match) and a large supply of decent ammo for more general practice. everything else can wait a long while

      • Your reply indicates we disagree. I don’t think we do. A quality barrel and lots of thoughtful trigger time with decent ammunition is the best way to start. Perhaps I should also add in “reasonable expectations” as well.

  4. why waste all that money rebuilding a new rifle just trying to make it shoot 1 hole groups at100 yds. why not just go buy a rock river national match and be done with it . iron sights 10 rounds 100 yds. 1 ragged hole. have not shot mine in a while but it shoots like that with hand loaded ammo 60 gr. sierra H.P.B.T. No problem. I could rebuild it but it would not shoot any better. so save money. Buy a Rock River!

    • Not sure who you are asking this to. The gun used in the article is a rack grade colt 6920 as it came from the factory, it has not been “rebuilt” or tweaked. We do not advise anyone who reads this website to buy any rock river arms Ar15. they have proven to be junk time and time again for all of us here. they are not built to spec, they usually don’t even stake the carrier key properly. In the past I owned 4 RRA rifles, the service rifle , a standard A4 and two of the varmint/target models. all garbage. So save the money and go buy a colt or KAC or put one together yourself, even if you ahve no clue how to put one together you got a 80 percent chance of putting together a gun better than RRA does

    • YES YES YES Well spoken,my rock river with the same bullet will shoot 1 hole at 100 yds.that is with iron sights on a rest handloads!


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