Mostly interested in a good round ball load. Thought I would empty some hulls for the project and started with some Winchester rifled slugs I had laying around. This barrel is a 12 gauge. Shooting offhand to make it more fun I put three touching at 40 yards, all 6 inches low as the barrel is sighted in for a discontinued Lightfield loading. I had never shot rifled slugs other than Brennekes in a rifled barrel and was very surprised to see my bore had picked up zero leading, in fact looks spotless, the point I had cleaned it to before shooting the ten total slugs. Now I am rethinking doing any loading until my stash of factory loaded slugs is shot up and this could be never because generally I use a slug gun just a couple of times a year. The gun is a Remington 870 and the barrel is a Mossberg made barrel. On the other hand I do a lot of loading and shooting just for the fun of it and would still like to play with a milder loading using a round ball, say pushed to 12-1300fps. Not sure but I would like to be able to use already loaded shot shells, pouring the shot out, setting the ball to the right height and roll crimping it into place. Since I am cheap and I have a case of Remington heavy dove loads I would like to start there. They are loaded with 1 1/8ths of 7 1/2 shot. After reading all the round ball threads, great reading I figure I have two choices. The .662 or the .690 round ball. It would seem using paper or plumbers tape to wrap the .662 ball would certainly work and the .690 ball might work if the shot cups were not too thick. If I had my druthers I would rather just drop a .690 on top of a hard card wad or two in the shot cup, a measure of COW and roll crimp but that would depend on the petal thickness of the shot cup. .735 - .690 would be .045 so the thickness I would be looking for would be near .0225 or so right? Am I guestimating the wrong total diameter of the OD of the shot cup?