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Old January 27, 2020, 08:14 PM   #281
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Join Date: March 2, 2014
Posts: 6,861
1.715" barely closes with feel
Likely 1.713 given tape compression.
Done with a case?--the ptg gage is a very good one--probably not 1.713 would be my guess--so I'm calling it 1.714--which in turn means CMMG "did it right."
How could the bolt close in that condition? One thing about the Stoner design (and unlike Garand's) is that the bolt's gotta be pretty-well fully rotated before the firing pin will protrude far enough to ignite the primer.
I've seen too many cases with rims bent--especially the failed or bulge cases--that I can't come up with an alternative explanation. I'd be glad to hear one if you have suggestions. The firing pin clearance is a very good point--forgot about that. Still there must be some kind of asymmetric pressure on case rim upon ignition--it is consistent in all the cases with bulges. The only other factor I can keep coming back to is the overall headspace "slack."

Here's the fired hornady AW case--it looks very much like your handload bulged case.

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Last edited by stagpanther; January 28, 2020 at 07:56 PM.
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