M1A1 problem

N

Northwest Cajun

New member
Hi guys,
I have a new SA M1A Standard model with a Mccann's scope mount and a Bushnell 10x Mil dot scope on it . My problem is with a full mag, the first shot is 3" left and 3" up from zero, I adjust scope to center and by the end of the mag, I'm getting a decent 1" group.I fill the mag and it is back to 3" high and 3" left on the first shot with a fresh mag. My target started @ 30 yds then moved to 100yds. It happened twice at both distances.

The scope mount and rings were installed by a gunsmith with blue lock-tite. Thinking it might be the scope I switched scope & rings and the same thing happened, this time with a Burris Signature 3-9. The ammo used was surplus Portugiese.
One guy at the range suggested that it might be the gas plug, Could that be the cause?
Any suggestions are greatly appreicated
Cajun
 
If the folks here can't help, you might try the CSP site at www.jouster.com. There is an M1/M14/M1A forum with some pretty knowledgeable folks.

You don't say how long it takes you to fill a mag (I assume you have only one) but it sounds like something is warping the barrel as it heats, then when it cools the zero goes back where it was. Try waiting several minutes (patience is its own reward) between shots and see what happens. (Use the same point of aim and don't adjust the scope in that period, you are shooting for a group.) I suspect the result will be a group 3" up and 3" left, and you will know heating is the problem.

In a case like this, trying to chase the shots by adjusting the scope is self defeating, because the rifle will go right back when it cools. If you fire as you have been doing with the same point of aim and not adjusting the scope, you would be able to see the shots "walking" on the target.

There are a number of possibilities for fixing the problem, but a long distance analysis just is not possible. Also, it depends in part on what results you want and how much you want to spend. There are books on accurizing the M14/M1A, and several companies that specialize in the work, like www.fulton-armory.com.

If the rifle is new, try calling Springfield and see what they say. They have a pretty good customer service reputation.

Jim
 
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