Originally Posted by JLA
That seems common to long leade milsurp rifles. Almost all the milsurp bolt actions i have tinkered with preferred a good jam. Problem with some is the leade is so much theres barely any case on the bullet. My finn 39 comes to mind. Itll shoot ragged holes if i seat to the lands with a 174 SMK, but any less and it quickly spreads the groups out. So i seat em where the rifle wants em and put a fair crimp to keep the bullets still during loading and feeding.
I also had a British enfield #4 mk 1 .303 that wouldnt shoot unless the brass was necksized ONLY, and had at least .2" of jump. Dunno, what the deal was with that one. I must have wasted 1000 bullets and 3 pounds of powder trying to figure it out.
Unfortunately, there is not enough bullet left in the neck to crimp. This rifle is a new CZ 550 American. It will shoot other bullets seated deeper, but not the berger. Unfortunately, it won't shoot anything as good as it shoots the berger. Its favorite powder just happens to be supreme 780 filled half way up the case neck. There is so much of it, that you get hit by unburned flakes coming out the muzzle brake. But having said all that, it is a tack driver with that dysfunctional load. I have also observed the same thing you mentioned in military surplus rifles. My theory is that the riflings are set way back to handle the round nose ammo the european nations fed them.