W.M.large

[Slugun45]

I'd say there is a very slim chance of this being a slug gun. Many of the modern era ( 1930's, 40's, and 50's) smith's put false muzzle on their round ball bench guns. Spence and Wolf to name two. The twist is likely to be 1 in 72 so you can beef up the load. 165 to 185 grains of 2ff, but check that drum and nipple before you shoot it. The patch ball combination mentioned earlier sounds about right. Have fun. Jim