Primer Cratering

[Blackwood Outdoors]

At what stage would you consider not going any further with load development. This is 25.2gr of N130 using 40gr varmageddon heads, its pushing 3750fps, so fairly motoring and the group is tiny 1/4-1/2" and SD is low. Although the primer has started to crater slightly, I'm not so bothered about the primer, just mainly the brass life , the max book load is 25.5gr.

 

[Muir]

I'd stop there. Is that primer backed out of the case?~Muir

 

[Cyres]

Is that a standard CCI primer? if so suggest you use harder primers eg Remington 7 1/2 bench rest.

Lots of threads on here about such issues and potential solutions.

D

 

[Blackwood Outdoors]

Yes CCI Primers.. Better Image

 

[Edinburgh Rifles]

Those primers will crater at significantly lower pressures under the wrong/right circumstances
mine do in .222 at much more modest figures with my firing pin/bolt dimensions

but if you have 1/4-1/2" and 3700+ what further development do you need?

i wouldn't be backing it off slightly if you can keep accuracy
hornady brass is not the greatest IMO so I would t expect 10+ firings if FL sizing with an expander ball die

 

[takbok]

I get the same cratering with my Sako. The primer looks flat enough to not go higher.

 

[Blackwood Outdoors]

Groups are good with this load SD of 12.8 with a 5 rounds, not sure wether to back off down to 24.4gr which provides similar groups and spread albeit 100fps slower.

 

[triggersqueezer]

you could have an es of 64 and still have a sd of 12.8 . i would use es myself.i would run it through an app and see what difference 100 fps makes to wind drift at the ranges your going to shoot. if its worth less barrel life and shorter lasting brass then great. personally i would run 100 fps slower.