This is my .450 Alaskan, a Single Shot M71/1876 Mauser. I use only light loads, of course, BP type - in smokeless or real black powder. The new .348 Winchester brass is easily necked up and fireformed with about any load. The resulting case capacity is about 97-99gr. of water, 5 to 7gr. more than a .458 Win. Mag case. In a strong action like the Siamese Mauser, it can be a formidable elephant ctg. or loaded down like a .45/70 BP ctg. if you wish. H4895 will run the gamut from mild to wild.