Ballistically speaking, and out to 50 yards, a .54 cal. 8" to 10" barreled flint pistol capable of firing 55 to 70gr. of 3F with a .530" or .535" patched ball will work just fine on moose or elk with proper hits.

It's ballistics will rival a S&W.44 mag with 4" or 5" barrel loaded to the nuts - but, it wil have but one shot until it is reloaded. Best to carry two.

This is a Wheellock - German Dag of around 17th century in design - although of older design is more accurate and quicker firing than any flintlock in it's prime.