Precision Test

Decided to go to the range some time back and perform a precision test with an AR15. This particular rifle was an M16A4 clone, with certain modifications: namely a free-float quad rail by LaRue tactical. There were no barrel or trigger upgrades. In fact, the barrel is a Del-Ton 20" government profile 1:9 twist, not chrome lined. 

Many on the internet would dismiss this barrel as being hardly worth the effort, but I have a different opinion, and let me show you why.

Except as noted, each ammo tested was a 5-shot group. All shots were fired from 100 yards. I used a 14x scope, and rested the free-floated rifle on a ruck sack. 

First up, I fired a group with Winchester 69-grain match ammo (black box). Impressive results. In fact, this 1" group was the best group I fired all day:

Next up was Federal Premium, 77-grain match ammo. As has always been my experience, the 1:9 twist barrel handled the 70+ grain projectile perfectly. The group measured just over 1.5" - which is comparable to the group I got with my SPR barrel.

Next up was Winchester Ranger 69 grain ammo. This box of ammo is at least 7 years old. It grouped well for me, at under 1.5 inches:

Next up was Hornady 75-grain BTHP Match .223. This barrel not only handled the 70+ grain ammo beautifully again, but actually got a better group with it than my $400+ White Oak SPR barrel. Just over an inch:

Next I fired a group with Hornady 75-grain BTHP match 5.56. As with the SPR, the 5.56 Hornady group was slightly larger than the .223 Hornady. Still, dang fine group at under 1.5". Also, note the trend with the 1:9 barrel and the 70+ grain ammo:

Fiocchi 77 grain HPBT Sierra Match King rounds were up next. This stuff was almost perfect out of my SPR barrel, but opened up a bit for the A4 barrel. Even if you count the one shot as a flier (I do not), the group was over 1.5", which is noticeably more than the sub-1" group this ammo got from my SPR. Still, not a bad group... and say, what was that about 70+ grain ammo and 1:9 barrels???

Nosler 77 grain HPBT match ammo was next. Very nice group. As expected, no issues with 70+ grain ammo out of a 20" 1:9 twist barrel. 

Next up was Hornady HPR 75- grain ammo. Previously, I'd noticed that this ammo does not perform as well as typical Hornady match ammo in my SPR. But how would it do in the A4 barrel? And would it even make it to the target in a straight line out of a 1:9 barrel? 2.5" group, and no keyholes. Neither result is a surprise:

Federal Premium 69 grain was the last high-quality ammo I tested. This ammo gets the best results out of my SPR barrel - under 1 inch. In the A4 barrel, it does remarkably well. The group was just over an inch. 

For posterity, here is a group with some PPU 55-grain ammo. It is M193 clone ammo. As expected, it is about 4 MOA ammo. By this point, you should realize it is the ammo here, not the barrel. 

Conclusions:

• 70+ grain ammo not being stabilized out of a 1:9 twist barrel is a myth when the barrel is 20" long. I have no data or proof for the claim one way or the other for 18, 16, or 14.5" barrels. 
• This government profile barrel is exceptionally accurate. Makes me wonder what could be done with some nice hand loads and a great trigger?
• If you were to do nothing other than free-float an M16A4 clone rifle, and feed it decent ammo, you would have one heck of a Designated Marksman rifle. Clearly, it can approach the performance of a high-dollar precision barrel.
• It is easier to fire a good group with a 14x scope than with a 3x scope. Yes, I tried. No, I did not take a picture. That should tell you how bad it was!
• FN, Colt, and Bravo make really good chrome lined. 1:7 twist. government profile. 20" barrels. They are all known for reliability and accuracy. This was a "bottom-feeder" barrel. Imagine how much better a good barrel might have done!

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