I found an English Sporting rifle I really like. It’s .58 cal. I have several .54s and one .58, a Buffalo Hunter carbine with a round balls twist. I like the trajectory and effectiveness of my .54s. My sole .58 is accurate and I can shoot for hunting to 100- yards with it using a 100 grain load. I don’t want a .58 that has no advantage over the .54. I want to shoot PRB. What I see on paper is a pretty heavy charge to get maybe 1200 FPS in the .58 with round ball. Any experience or advice? It’s a fairly expensive rifle so I need to be serious if I go ahead with the purchase.