Gun or die problem

[ron]

Answer is,

I reload match grade M1A and bolt guns. The shoulder of the case is not sized enough! The sizer die can be screwed down past the point it bottoms out.
I have found case gauges do not work for match grade chambers! The RCBS precision mike will measure the shoulder of the case. Bring the shoulder a few thousands pass zero.
Compare new ammo, fired cases and sized cases to bring the shoulder down to factory ammo specs.

RCBS Precision Mic 308 Winchester

 

[deadshot2]

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I have found case gauges do not work for match grade chambers!

Most case gauges, unless they were cut with an actual chamber reamer, don't do anything other than show if the case will properly headspace. Too loose in the body portion to show whether a case is too large to chamber properly.

Have your gunsmith cut a piece of scrap barrel material with a chamber gauge, preferably the same as he used to cut your rifle's chamber, an use it to check your ammo.