Yet another pierced primer thread... (pin hole in primer radius)

[358WCF]

I've witnessed 2 shooters have WW primers crack around the edge radius and from what I see from Mr Dibble is different as it's more a blow hole not an edge crack.
At that time it was near impossible to find other shooters experiencing WW primer failures of the same type but one I found in Aussie whom was also pushing things hard.
In both cases (6mm Rem and 270Win) they were hot loads carefully developed a little beyond anything you will see in print.
Both shooters had used WW primers for some good while and both now use something else.

Odd... the OPs pics look exactly like a number of pics of failed WW primers that I've seen on the web, as well as the Federals that went south on me. No excess pressure, not even to the "warm" point on my Fed. failures (happened during the lower charges of load development). Most of the people posting the WW pics were sure they weren't excessive loads either. It's the internet, so who really knows?

I see what looks like a crack (longer than it is wide) across the radius after a high temp/pressure flame burns away some of the edges. Blow hole? WTF is that & what does it look like? Please enlighten us.

 

[Webster]

My guess is the base of the case is not being pushed back against the bolt face. Meaning the shoulder is being pushed back too far when resizing. This causes the primer to mushroom and bulge at the base. It then blows out the side of the primer.

Below you can see how far the primers were protruding and unsupported when fired.

View attachment 1444505
Below shows how a normal primer is pushed back and reseated.

Above photo: It looks like the region of the crack has a larger diameter than the rest of the cup. Looks like a large part of the cup was not supported by the case pocket. Never saw this in many years of reloading. Could be the result of several issues. It's normal to try and blame a problem on one thing.