The recoil should be about identical in identical rifles to the .416 Rigby. About the same amount of powder, same bullet weight and about same velocity. The reduced bearing length of the .440" bullet would probably make no difference in felt recoil - only stock design & gun weight would tell. I wouldn't shoot it either.
103gr. 4350 - 401gr. - 2,360fps - COTW.
Factor Load - 401gr. - 2,438fps - COTW.