Originally Posted by passagenight
Ok, understood; I think...but I have a Marlin 1895 and a Ruger #1 both chambered for the 45/70. I reload, and have done so safely so far. These are rimmed cases of course which would define the headspace as being almost immaterial?.......but some rounds will chamber in the Marlin and will not chamber in the Ruger. The difference seems to be the 'taper' of the bullets used. If tapered the Ruger will chamber; if 'rounded' it hangs up just in front of the rim. Of course I don't force this.
Is this a case where the bullet is engaging the rifleing of the barrel on it's curvature?
It sure sounds like that's your problem. Are you seeing marks from the rifling on the round nose bullets?