AR Sponsor
Posted: 8/19/2007 3:49:16 PM EDT
 Shot some of this yesterday during a function check for my Model 603 build and it was keyholing like an SOB. The barrel twist on my rifle is 1/12. The bullet weight is 50 grains. I was sure the twist rate would be fast enough to stabilize the rounds. Thoughts? 
|
|
Is it possible that you were shooting say, from the hip and you were hitting the ground first and the ricochet looked like a keyhole. I looked at a target once and it had a keyhole in it. Then I realized that it was a "bounced" bullet that caused it. How much of a keyhole did you have? Was it a 90 degree turn or a slight oblong hole? 1 in 12 will stabilize a 50 grain. |
100 rounds out of 100 rounds made perfect bullet outlines in the target at 25 meters. I was at an indoor range, hence the short distance and frangible ammo. |
|
Doc, When you fire retro rifles, use retro type ammo like M193 ball or M196 tracer. As previously stated above, the AA40 bullet is much too long to be stabilized by your early 1x12 twist barrel. A 50gr. AA40 bullet is shown at top, a 63gr. M856 Tracer in the middle, and a 77gr. AA53 MK262MOD1 Sierra MK on the bottom. The heaviest bullet I was able to stabilize in the 1x12 twist was a 70gr. Speer Semi-Spitzer. The Semi-Spitzer design kept that bullet short enough to stabilize out of the 1X12 barrels in use in the '70s. That load shot circles around M193 ammo and I used it to place is a few matches in the '70s & early '80s. Carey  |
AR Sponsor
Win a FREE Membership!
Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!
You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.