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?
Printable View
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
barrel profile, twist ratio and rollmarks
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.
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
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.
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.
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....