Thompson Center Hawken, Renegade, New Englander, White Mountain Carbine, can all be had in .54 caliber. They will all shoot a patched round ball with accuracy. I own each one in .54, and shoot patched round balls every weekend with one of them. Also the Lyman Deerstalker, is a good roundball shooter in .54 caliber. They are all 1 in 48" twist, allthough some of the Hawkens, and Renegades came with 1 in 66" barrels, but are much less common.