Let's assume we have two cartridges of the same caliber, each equally loaded. Same powder, same charge, same bullet weight, same bullet diameter. The only difference being one is loaded with a cast and the other loaded with a jacketed. Which will generate higher chamber pressure? There is a difference in the bullet material. One will have to generate different results. Who knows the answer to this?
I have asked this question of many people and have gotten many answers. Unfortunately, none of the answers have been applicable to the question! So much for admitting "I don't know".

The floor is open.

Puncher

Cast bullets are supposed to give higher velocities with lower pressures with everything else being equal. In loading for my revolvers I can usually go with a higher charge with cast bullets of the same weight vs a jacketed bullet. Like a 300 Lswc vs 300xtp. This will bring me up to the same pressure with alot more increase in velocity. The cast bullets are supposed to offer less resistance to going down the bore and deform to fit the rifleings easier. There has been a couple of articles done by John Taffin on the subject.

What Lar45 said is the way I have it figured too.

The jacketed bullet will produce higher pressure.
wort

I really have to commend you guys. Y'all are the few that I got straight answers from. Thank you.

Puncher