About power/penetration/ability to do work - John Taylor reportedly used a .577/450 Martini sporter with BP factory ammo for a while. That round from his rifle, developed about 1,340fps with the 480gr. paper patched bullet - usually of pure or almost pure lead.

The .500 S&W is more powerful than that but much more difficult to shoot accurately so all one has to do, is to put the bullet where it will do the most good/damage - that will be the challenge.