PP Bullets in a Tube Magazine Rifle?

[Flash Pan Dan]

I just slugged the chamber mouth and lead and found there is hardly any lead at all. The chamber mouth measures .342, the lead is .09 long and measures .323 just before the 5 groove rifling. So I'm thinking I should get a mould that casts .318 slick since two wraps of my favorite paper adds .0055 to the diameter. I'm surprised by how short the lead is in this chamber it almost makes me want to try patching to bore size and giving it a try with black powder. But I am limited by the cartridge length since this is lever gun. I am most appreciative of all the help.