Primer cratering.. SOLVED THANKS FOLKS!

[ckaberna]

Check out what I ran across today. The I was shooting Berger 108’s in a 6BR improved with H4895 and CCI450’s with .010 jump. Never shot 108 before so was working up in groups of 3.
At 30.3 one of the three is on the left others fine
30.5 is the middle of pic one of three others fine
30.7 all 3 looked like the one on the right. Ok, right?
Only reason I kept going is it was one of three in the load range the FPS at the 30.7 is only 2900 with an Oheler 35p.
Why would this happen randomly then not at higher pressures/ loads?
Need pin bushed? It’s a bat action.
Thanks

 

[243winxb]

Firing pin spring problem? Weak. A guess.

 

[KenOath]

Could be a sign of high pressure, I had the same thing with 400s but same load worked with 450s. Obviously proceed with caution..

 

[mr45man]

Can't really see enough detail.

 

[KenOath]

Can't really see enough detail.

True...at a glance I assumed the centre piece was pearced, taking a closer look it may not be..

 

[ckaberna]

Not pierced but the cratering is like nothing I have seen in my limited experience. I will try and get better pics. This “cratering “ measures .020” above the base of the case.

 

[ckaberna]

 

[BRGUY]

You still have good radius around the edge of the primers, which is a good thing!

A couple of things that you could do -

Change to a primer with a harder cup...

Get a replacement bolt...

Get an oversize firing pin...

Bush the bolt face...

I have been reloading for 50 years now, and I have NEVER seen a primer crater that much!

Something definitely needs to be changed, right now, real quick like and in a hurry!

 

[mr45man]

I have seen that on a bolt/firing pin slop fit.
But not on a Bat action.?

 

[KenOath]

You still have good radius around the edge of the primers, which is a good thing!

A couple of things that you could do -

Change to a primer with a harder cup...

Get a replacement bolt...

Get an oversize firing pin...

Bush the bolt face...

I have been reloading for 50 years now, and I have NEVER seen a primer crater that much!

Something definitely needs to be changed, right now, real quick like and in a hurry!

Is there a much harder cup than the CCI450?

 

[BRGUY]

Is there a much harder cup than the CCI450?

I cannot give you an honest answer on that, I do not know. I was just offering suggestions.

My Winchester M70 cratered primers with ALL AMMO! I bushed the bolt face and matched it to the firing pin. Problem solved.

 

[ckaberna]

That was my thinking.... harder than the 450? I think something is wrong with my action/bolt? That’s the weirdest cratering I have ever seen .020 above the base. Maybe bad lot of primers?

 

[ridgeway]

It's the firing pin spring. Replace is beginning of every season.

 

[243winxb]

If the firing pin was in contact with the prime, there would be no primer flow into the firing pin hole.
Clean the firing pin channel and get a new spring.

Or reduce the load if above fails.

 

[LRPV]

Is it an S length action by chance? Get yourself a new firing pin spring.

 

[ckaberna]

Is it an S length action by chance? Get yourself a new firing pin spring.

Bat “B”

 

[LRPV]

Bat “B”

I think a new spring will fix it.

 

[X-Caveman]

I had the exact same thing happen to me with a Panda/ BRA/ H4895/ CCI400/ BIB104 combo. Mine was a new Broughton. My panda has the small pin hole. I was out doing a little speed ladder and wasn’t paying attention (thought I was well within normal “safe” zone) & actually blanked two primers. The others looked like yours. They all looked bad from 29.9gr to 30.2gr and finally blanked at 30.26 & 30.30 (2,935 FPS). I switched to a Russian primer and no signs of pressure whatsoever. I also changed my firing pin spring this morning.

Lesson learned. I got lucky not to hurt myself or my trigger.

 

[ckaberna]

I am having a difficult time understanding how a weak spring would do this. I will research it. Just have never thought about it.

 

[ridgeway]

I am having a difficult time understanding how a weak spring would do this. I will research it. Just have never thought about it.

Believe it or not...it's a fact. It's not just a BAT thing. How old is your BAT? They changed the spring and pin diameter after 2014 I think. Went from .240 to .280. If you have the .240 pin/spring....I'd recommend upgrading to the heavier .280 pin and spring.