Mr Guffey,
Cut a 5 or 6 in long piece of 1/4 in brass rod. Stand one of your 7x57 Mausers vertical,and drop the brass rod down the muzzle,to rest on the bolt face,chamber clear(unloaded) and cocked. Muzzle still up,pull the trigger.
That piece of brass rod will exit the muzzle.
Point,striker impuse is significant.
Point two,the striker impulse occurs first,to initiate primer ignition.
Unless you super glue your brass to the bolt face,what supernatural force holds the case head tight to the bolt face,assuming there is some(even .002) head clearance?
So,as designed,the chamber shoulder will act as an anvil to limit the cartrides forward reaction to the striker impact.
Primer fires! Primer will back out to the bolt face,pressure in the primer pocket will hold the cartridge forward in the chamber
Pressure builds,case head returns to bolt face.
It will probably help you understand,Mr Guffey,if you watch the little cartoons from Varmint Al's web page Finite Element Analysis on the effects of chamber surface finish.
It must feel lonely,being the Only Reloader Who Knows.
Maybe with Varmint Al's animations,you can learn something. Then you won't have to be The Lonely Only Reloader anymore.
Doesn't that sound nice?
http://www.varmintal.com/a243z.htm