Originally Posted by
SA Friday
Last thing I would check it to see if you actually NEED to crimp the cartridges. I have very little M1A experience, but I would work off the hypothesis that crimp isn't needed until I tested it and saw enough set-back for me to start crimping the rounds. This is pretty easy to test. Once you have found some brass that will fully chamber, make a round that is fully resized and the bullet seated to about 2.80", no primer or powder. Then load it in the gun from the mag like you normally would. Remove the round and measure the OAL and see if the bullet was set back into the case. Anything over 0.1" is probably too much and a very very small amount of crimp will stop the movement.