Thoughts on pressure signs?

[Ucsdryder]

6.5 creedmoor
H4350
Lapua brass
SRP
143 eldx

worked from 39g to 42.9g
Max velocity was 2748 with 42.9gr.

Would this be considered an issue regarding the primers cratering? These pictures are at 42.9. I don’t see any extractor marks or primer flattening but maybe someone more experienced can tell me?

on a separate note it was hard to gather much from the ladder test. The velocities were up and down quite a bit.

 

[BBob]

Cratering can happen on lowish pressure if pin to bolt fit is loose. I'd put more stock in flattening primers and ejector marks. Cratering and pin fit is overly worried about IMO, I personally ignore it for the most part.

 

[WCB]

I agree with above. No swiping, not sticky extraction, from what I can tell the primers do not look flattened. Probably sloppy firing pin to channel fit.

 

[fightthenoise]

Primer cratering is one of, if not the most ambiguous signs of pressure. So much so that I barely pay attention to it anymore. I pay the most attention to bolt lift and velocity spikes. Sounds like velocity isn’t helping you, but if the bolt lift was the same throughout the test I’d say you’re still safe. Your max velocity doesn’t seem too good to be true either.

 

[BBob]

Here's an experiment for you. Polish that pin tip to a mirror finish and watch what happens to the craters.

 

[Ucsdryder]

I saw a similar cratering with 37.5 gr which was minimum powder charge, but it definitely stuck up higher with the max charge I tried.

 

[Ucsdryder]

42.9gr of h4350 seems to be way above what I’m seeing in any books or most “pet loads” on the internet. This gave me more pause than the primer marks.

 

[wind gypsy]

What rifle/barrel length?
What primer?

I agree with the others, looks like a product of loose firing pin/bolt face fit and softer primers. I bet a CCI 450 would show less but good luck finding em!

Unless it’s a really slow or short barrel, you should have no concerns at that velocity.

 

[Ucsdryder]

Savage 110 long range hunter 24” barrel
Remington bench rest 7 1/2