I have just become the lucky owner of an Alexander Henry double hammer gun in 450 BPE. I've made a cast of the throat and muzzle and note a definite taper to the bore from .458 to .455. Being new to the mysteries of Henry rifling, would anyone have suggestions on a bullet to start working up some loads? Paper patched? Any advice is welcome, thanks.

Also, this rifle has a folding peep sight on the tang, adjustable for elevation only, and looks to be part of the original manufacture, not added later. Has anyone seen this on other Henrys?