I have a hammer Colindian and made a mold for it very similar to a solid nose version of what Marrakai showed. In my case the bore is .018" out of round so I made the bullet the average diameter or .009" over minimum diameter and of course .009" under maximum. I have only shot the gun a little and am undecided as to whether I should have made the slug larger or not.
I load with 3 drams of 2F black powder (80 grains) then a cushion wad and finally a slug.
With 7 1/2 shot, the gun gives a pretty open pattern and I would consider it to be a 30 yard gun; good for skeet but certainly not something to take duck hunting.
It is a while since I measured the bore and forget the dimensions but also would not be surprised if these varied a bit over the years of production.
cheers Doug
