A friend of mine here in Germany just came up with a Peabody sporting rifle that appears to be a 45-50. It included some brass from BELL. Rims are too thick so the casings have now been turned.

Anyone have a pet load for this cartridge?

A bit late to the Post here.
In 2009, came up with a Peabody Hunters Gun, .45-50 Peabody.

Also in 2009, stopped by the home of the late Tom Ballard, here in Montana (noted bullet mold maker) and he cut a new mold that produced a 315 gr .457 cast bullet.

I contacted, at the old name then, Miles City Powder Company, Montana.  Their enginer at the time was provided with the necessary information he required: barrel twist, case capacity, bullet weight, powder wanting to use, etc.

He suggested starting with 20.0 grs of 5744 powder.
Using Buffalo Arms Co .45-50 Peabody brass (reworked .348 Winchester brass), this load would produce 2" groups at 100 yards.  Pleanty fine for my needs from an 1870's era rifle and is the load that I have used since then.