gas cutting on .308 ruger bolt

[Rachael]

I've found that the bolt on my .308 is showing gas cutting at the primer ring.
The load is only 41grns AR2206 CCI PRIMERS cases are ex Aus Mill. and Primers are a tight fit when reloading.
Projectile is 168 grn. Match at 2600ft per sec. I am not sure but it seems to have started when I dropped the load from 43grns.
I was useing Lake City 175 grn 1972 Match/Sniper ammo. I put about 1000 of these through it with no trouble.

THANKS GUYS
RACHAEL

[COLLECTOR 1]

Hi there.....

If you can knock out some of spent primers and check if they have been slightly punctured by the firing pin. I've found some batches of CCI primers a bit to brittle at times, and they are notoriously "hard". That's a starting point, or even try another brand of primer. I've always used Winchester large rifle and find them great.

I'm betting it's something to do with the firing pin ever so slightly rupturing the primer on ignition.

Good luck

Collector 1

[Herdsman]

How deep is the pitting at this point? Just a visible ring or deeper?

[Rachael]

How deep is the pitting at this point? Just a visible ring or deeper?

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The pitting is about .004" deep.
It is the Dia. of the Primer Pocket,
Fault is not Firing pin as under a Microscope it is still smooth and shows no gass cutting.
I don't want to change the load to much as it shoots 3" groups at 600 mtrs.

Thanks
Rachael

[COLLECTOR 1]

Do the primers show any sort of "puncturing" or "rupturing" under the microscope .....

Collector 1

[<<Genesis93>>]

Damage is done.....

You say ex-Mil brass? ( < your answer may lie there )

If you're happy with the load carry on, damage is done and at this point is 'cosmetic' or visual only... but the erosion of the bolt face started with the 43gr loads no doubt.
If you want to reduce the occurrence - you may need to switch to commercial brass but you may need to develop you load again...