Colt 6920 VS 6720 Accuracy

[razorback2003]

I am thinking about an AR 15 and would like to know the accuracy difference between a Colt 6920 and a Colt 6720. I would put a quality scope on the rifle and shoot quality ammo or reloads. The 6720 looks good because it is lighter weight than the 6920, but if it doesn't group as well, not sure if I would go with it.

 

[eldon519]

They should be pretty comparable.

Here is a nice accuracy write-up for a lightweight Colt. Only tested one load, but averaged 1.69" ten-shot groups. That's pretty darn good.

https://www.ar15.com/mobile/topic.html?b=3&f=118&t=486023

 

[Mosin Bubba]

Isn't the 6720 just a 6920 with a pencil barrel?

Mechanically, they should have pretty much the same accuracy.

 

[eldon519]

Yeah the barrel profile is the difference.

Also worth noting, I love my 6720 and would recommend it to anyone.

 

[Jackal]

Cold bore accuracy will be basically the same. Pencil barrels do tend to open up a little as the barrel heats quite quickly (also cools quickly).

 

[taliv]

hard to tell what you're really looking for, based on the scope comment and question about accuracy.... you know that's not a precision rifle, right? it's the gold standard for carbines but if you're looking for something to groups with, or to shoot off a bench, keep looking

 

[Missouri Farmer]

I've shot a 6920 and FWIW did not find it to be a heavy carbine at all although it does have the thicker barrel.

 

[md7]

Initial accuracy should be similar between the two, with groups opening up a bit more with the pencil barrel as it heats up. Each barrel is a law unto itself, but I'd imagine that 1.5" to 2.5" (maybe even 3") groups could be expected from either with m193 or m855. You'd likely obtain better groups with higher quality ammunition.

To me, accuracy and precision mean two different things. Both of the rifles in question should provide decent accuracy for what they are, and in their stock configuration. Neither is what I'd think of as a precision rifle though, if that's your goal here. If you're simply looking to score hits somewhere within COM on a torso sized target at 300-400 yds with mil spec ammo either should be capable of delivering that level of performance.

Hope you find what you're looking for. Best of luck to you.

 

[eldon519]

Well keep in mind a 6920 barrel is skinny under the handguards as well, where the barrel gets the hottest. The front sight base acts like a big cooling fin, and barrel heat forward of the FSB is not the problem. It is fat where it should be skinny and skinny where it should be fat. Similarly for accuracy, a barrel would be stiffer if it were fat at the base and tapering towards the muzzle. The 6920 does pretty much the opposite of that.

As mentioned, neither is a precision rifle, but they both should offer plenty of practical accuracy.

 

[wanderinwalker]

I suspect accuracy differences between the pencil barrel and the Government profile barrel are likely to be more influenced by the individual barrel and ammunition than you can attribute to the barrel weight.

I second taliv in wondering what do you want to do with this carbine? I have a 6920 as I type this, and while it's reliable, I wouldn't classify it's accuracy much better than "good". It's certainly more than acceptable for my uses, as I bought it to turn money into noise and to sit behind the closet door, "just in case." Right now it's topped with an Aimpoint PRO red dot, which I feel compliments the rifle perfectly given its practical useful range.

Oh, accuracy: the best groups I've gotten out of my particular example are right around 2" at 100 yards for 10-shots, using handloaded Hornady 75gr BTHP match bullets. Using the iron sights it came with. Handloaded 55gr FMJ varies from this, from about 2.5" using Hornady bullets to over 3" using, well, just about anybody else's FMJ pills. I haven't benched the rifle with factory ammo since I first got it, but I distinctly recall American Eagle 55gr FMJ being somewhere around mediocre, well over 3" groups.

But I don't spend much time trying to make pretty groups with my carbine. It gets used to bust clays hanging out at 50 and 100 yards, ringing steel out to 200 yards and of course ventilating lots of paper. All done from standing and improvised prone and sitting positions. At 200-yards, even with run of the mill FMJ ammo, a 10" steel plate is getting hit the majority of the time.