DRJ,

I'll be duplicating CptCurl's Alexander Henry .577 try out load:

65.0 grains IMR4198
Three .375" 24 gauge felt wads
Montana Precision swagged 560 gr. paper patch RN
Jamison .577 3" brass trimmed to 2.75"

I'll go up one grain until it regulates.

CptCurl ended up with 74 gr. for a velocity of 1750 fps, 3808ft/lbs and 2521 OKW.

I've been practicing patching with some straight shanked .458 lead bullets. With patience and some experimenting they came out looking really good. An office paper cutter is essential.