I stand corrected - bit sharper hump on the rear of the action, and of course, different guts.

COTW notes the .50-115 Bullard of 1886 (semi-rimmed) was chambered in the repeating rifles - Lever action, and 'perhaps' in the SS. It had a very slight shoulder, .577"dia. necked to a .547" neck, .015" per side.