head space problem

[rem700nut]

have 45-70 guide gun , if shoot rem factory .405 rn jsp at 1300fps no problem ,primers are normal , if shoot win 300 gr. hp at 1880 fps hornady .325 red tips at 2050 fps and my handloads of 43.0 gr imr 3031 and 405 gr lead fp at 1600 fps ,the primers protrude quite a bit . never seen this on any other rifle .Have another 1895 with 22 inch barrel and new win 1886 el ,shoot all the above ammo and primers are normal ,level with the rim when fired .Have used no-go gauge ,lever closes till it pushes the trigger safty lever half way into the stock ,squeezed as hard as i could but the lever would not fully seat ,so i gueiss the head space is ok ,Measured the expansion ring it is the same range as my other 1895 so i guess it isnt an overlarge chamber ,any ideas as to what is going on ? sorrry no pictures ,no camera

 

[Bwana John]

While Im not really sure what you just wrote, I think you stated that with minimum loads the primer sticks out from the case head after firing

Id guess your problem is resizing the brass too far, AND not enough pressure to make the brass set back against the bolt face.

 

[jim in Anchorage]

Actually he said the opposite[as I read it]-the low pressure load is OK, the HP loads are backing the primers out. Sizing in a straight wall case that headspaces on the rim can not cause this. My question is, what is "protrude quite a bit"?

 

[Ol` Joe]

Levers of some models will show some receiver flex with higher pressures. I don`t know if yours is one but I would suspect that this may be happening.
I`m sure someone here knows more about this then I and will jump in..

 

[jim in Anchorage]

Joe you are right about the flex. Not a lever, but my rear locking bolt Winchester M43 in .218 bee shows case separation on 1x fired brass from bolt flex. But the primer does not back out; the case gives. OK heres my wild theory- even the hot loads in a 45-70 do not exceed the strength of the brass, so you shoot a hot load, the firing pin pushes the case forward to the front of the rim, and the pressure "locks" it in place. The brass holds, so the primer backs out. Shoot a low pressure load, the firing pin pushes it forward, but there is not enough pressure to hold the case and it moves back to the bolt face,reseating the primer.