case separation

[Vern]

Yesterday I went to the range to test some pp loads in my 45/70. The first load wa 65 grains of FFG under a 540gr pp bullet from BACO. It shot very well giving me 5 10's out of 8 rounds. The second load was the same except for 70 grains of FFG. I have to compress these loads a lot. (1/2") I fired the 8 rounds and they shot very poorly. After I got home and was de-capping the cases I found that 4 of them had separated and that there were 4 others who had stretched out of tolerance. My thought is that I have to seat the bullets so deep in order to chamber them that the bullet is "bumping up" while still in the case and this is the cause of the separations. Does this sound right or am I missing something? :shock:

[felix]

Possibly correct. ... felix

[BPCR Bill]

Paper patch boolits are traditionally seated out quite a ways into the throat, and are usually in the case no more than 1/4" at most. And they are soft, I have the same boolits you have and they are 40:1. I think you are trying to shoot these as you would a grease groove, but you will have to wipe between shots to chamber a PP round as they were intended.

Regards,
Bill