I recently zeroed a Vortex Strikefire at 50 yards on my AR. Colt 6721. 16 inch heavy barrel, chome-lined, 1:9 twist.
I tried my first MK 262 77 grainers in it, knowing the twist rate is not ideal. At 50 yards they were significantly more accurate than m193 or m855. Right at moa, which is saying something considering I was shooting.
I know that this doesn't prove 1:9 barrels are as good as 1:7 with heavy bullets. Obviously, I was shooting at close range, before significant velocity loss. But it might be good to note that instability wasn't immediate. (Some posters, not here of course, seem to suggest heavy bullets do somersaults out of a 1:9.) When I get out again with the AR (might be a while because of work), I'll try 100 yards.
If you've shot 77 gr with a 1:9 barrel, what was the max range you kept typical groups without keyholing?
I tried my first MK 262 77 grainers in it, knowing the twist rate is not ideal. At 50 yards they were significantly more accurate than m193 or m855. Right at moa, which is saying something considering I was shooting.
I know that this doesn't prove 1:9 barrels are as good as 1:7 with heavy bullets. Obviously, I was shooting at close range, before significant velocity loss. But it might be good to note that instability wasn't immediate. (Some posters, not here of course, seem to suggest heavy bullets do somersaults out of a 1:9.) When I get out again with the AR (might be a while because of work), I'll try 100 yards.
If you've shot 77 gr with a 1:9 barrel, what was the max range you kept typical groups without keyholing?