RE: Buckshot in a Muzzleloading Shotgun
I shoot it out of a 12ga Pedersoli SxS. Your gun will tell you what size pellets and charge give the best pattern, the effective range will depend on how stout the charge is. I use 90grains of 2f Goex with 12-#1 pellets and won't even think about anything over 40 yards. I use a 1/4" cardboard wad over the powder, put the pellets in a dime wrapperand just stuff it down-the dime wrapper acts as an overshot wad. Pretty effective for me but you will have to put your time in at the patterning board, all guns are different.
Doug