F. Guffey, thanks for a very informative bit of info. I must agree with all you have said because its make a lot of sense and I will not debate any of it. I will just add; Because this particular rifle does not warrent any great amount of money spending I will not be reloading for it and just using factory ammo. Being older and retired now I have reloaded for many different cartridges and know exactly what you are saying. I agree feeler guages, mikes, venier calipers and other, some home made, measuring devices are invaluable in good reloading practices and I use many myself.
Remember this first ammo (Federal) has way under sized cases before and after firing, evidently, as I said earlier, to promote easy chambering and still be safe in "most" older, and maybe some rifles, with not much quality control.
Using these cases I recently did my own headspace check buy adding to an empty case, no primers, small round pieces of masking tape until the cartridge became somewhat diffucult to chamber. Remember that with a Mauser bolt you can close and open the bolt, in the middle position, with the firing pin cocked so there is no resistance to the bolt other then the round being chambered. Now I understand there is a small amount of tape crush doing this but it gave me a fair reading of bolt head to case measurement. I ended up with about .015. Probably out of Saami specs and why I am seeing some primer extrusion.
I will be doing some headspace checking, using this method, when I get some new ammo from Midway and will post the results.
Tobnpr said " Your fired case head dimension is almost .01 larger than unfired brass- too excessive." Respectfully but If you look closely you will see the case before and after firing measured, at the base, not the rim, just north of the extraction groove, .464. My reloading manuals all call out for a case to be .471 which shows mine are undersize even after firing. It could be also that when firing, the cases, which are all measuring the same, are not expanding enough, maybe light loaded for older rifles, to keep it from moving and therefor the primer extrusion.
New ammo will give me more info but might be closer to Saami specs for modern rifles but could be more powerful also so I'll be advancing very carefully. These older military rifles are somewhat a challenge to use safely.
Thanks for everyones input, I have learned a lot. And the quest continues.