Colt 6920 vs 6721 [Archive] - M4Carbine.net Forums

Roklok

11-15-09, 09:29

What is the difference between the Colt 6920 compared to the Colt 6721 other than the 6721 has a heavy barrel and a 1x9 twist?

Molon

11-15-09, 10:41

What is the difference between the Colt 6920 compared to the Colt 6721 other than the 6721 has a heavy barrel and a 1x9 twist?

That's the basic difference. With the appropriate bullets, the 6721 will be more accurate than the 6920.

http://www.box.net/shared/static/6po0sh394g.jpg

http://www.box.net/shared/static/8yz2obnogj.jpg

Frens

11-15-09, 13:40

barrel profile, twist ratio and rollmarks

sff70

11-15-09, 17:23

The previous posters nailed it (twist, HBAR).

I've owned both. Still have the 6920 and would buy another in a heartbeat.

Didn't care for the extra weight of the 6721. Not one bit.

metroATL

11-15-09, 19:10

Is there an advantage to an HBAR vs an m4 profile in a 16 inch rifle?

TOrrock

11-15-09, 19:41

Is there an advantage to an HBAR vs an m4 profile in a 16 inch rifle?

Maybe in a bench rest rifle, but not in a carbine that's going to be carried and shot off hand.

Molon

11-15-09, 19:54

Is there an advantage to an HBAR vs an m4 profile in a 16 inch rifle?

Accuracy. The pic below shows a comparison between a Colt 16" HBAR and a Colt 16" M4 (government profile) barrel. Three 10-shot groups were fired from each barrel at a distance of 100 yards. The 10-shot groups were over-layed on each other using RSI Shooting Lab and the mean radii were calculated for the 30-shot composite groups.

http://www.box.net/shared/static/d4f59k22os.jpg

Surf

11-15-09, 23:24

My Colt 16" 1:9 HBAR far out shoots any of my M4 profile barrels from any maker. The weight difference means little to me.

Frens

11-16-09, 03:22

I have a HBAR while other 2 friends of mine have a M4profile and a lightweight....all of 3 are 16'' Colt carbines.

during a dynamic shooting match I liked the extra weight of my hbar; the lightweight carbine recoil is too different for my taste.
but the M4profile is the perfect compromise.

Smuckatelli

11-16-09, 16:44

I had to trade my 6721 because my daughter needed to shoot out to 600 yards. The 1 x 7 twist handles heavier rounds better than the 1 x 9.

She used the my 6920 during her first match last June, afterthat I traded the 6721 for a RRA NM4....