Primer deformation

[realm-aw]

How much does a Fed 205 small rifle primer deform under maximum safe loads? Had a discussion with some guys at the range and opinions ranged from "any change in primer shoulder, at all" to "flattened is OK if case head is not expanded".

 

[realm-aw]

Thanks

German, Thanks for the reply. I was getting tired "range authorities" telling me all about my loads by reading my primers. If I'm understanding it correctely , you can know a little but you can't know a lot.

 

[John Kielly]

Additionally, as I found when I sized some cases recently with the wrong *^$$@! die, you get some pretty ugly primers when the headspace is a tad generous because of the riviting effect when the expanding case catches up with the primer on the bolt face.

 

[jackie schmidt]

Primers

German gives some good info. When it comes to primers, and how they look under a given load, it is good to have a personal relationship with your Rifle.

From a 100-200 YRD Benchrest Shooters point of view, it takes around 70,000 psi to flatten a Federal 205 to where there is no radius left on the outside edge. I consider that the upper end of the upper load window in a 6PPC when using a custom action.

Many shooters panic when they see a cratered primer. But, from my experience, primer cratering is usually a product of the firing pin to hole condition, rather than the actual pressure.

Here is an example. A friend at Tomball had a 308 built on a Remington Action. All he had done to the action was screw on a custom barrel. The load he was shooting was showing severe primer cratering, but the radius on the outer edge was still very pronounced. He was in a panic as to why such a mild load was producing so much pressure.

I stripped his bolt, and the best way to describe the firing pin to hole clearance was "on the big side of loose".

That is not uncommon in Factory Rifles. That is why observing the outer radius, and learning what it should look like in each Rifle, is so important.......jackie