M14 Forum banner

M1A and Odd Headspace Question

5K views 34 replies 15 participants last post by  canmancan 
SAAMI specs specify a shoulder angle of 20 degrees for a Winchester .308 and the shoulder angle spec for a 7.62x51 case is 40 degrees.
Not trying to snipe here, just a little clarification: SAAMI spec for .308 Win shoulder angle is 20 degrees from centerline. 7.62 NATO spec is 40 degrees overall, from shoulder to shoulder. It's the same angle...GI1
 
  • Like
Reactions: tonyben
Have you considered that you may be lengthening the cases when pulling them back over the expander ball of the sizing die during the downstroke after sizing?

Try sizing a case without the cecapping rod and expander ball installed as an easy check.
+1... my father ran a test on this. He has a Rem 700 with a really tight and true chamber. He would measure the case neck runout on fired cases and the necks would be almost perfectly true and straight, near zero runout. Then after resizing, he would measure again and not only were the cases stretched longer, but the expander ball would pull the necks out crooked, the necks had more runout after sizing than they did when they came out of the rem chamber after firing...
 
  • Like
Reactions: jmoore
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top