455 Gnr is it for G2 or Encore?

There s a factor of area, the "i" in psi. The more area the more lbs. thrust on the "i" factor. The smaller area the less thrust force. A 50,000 psi .223 case head is tiny and low stress on the locking bolts, the .45/70 or .50 cal. is several times more and imparts more of that lbs. thrust because the is more area.

So the little rounds can be hotted up and the larger cases need to be held back some. Pressure X area = thrust.