I always wanted a 'coach gun' and recently scratch that itch; I now have a 12 gauge Stoeger/IGA with 18-1/2" barrels. But they are choked, modified and improved cylinder. It's intended use is hand-thrown clay pigeons in the desert and intruders at very short range. Modified is a less than ideal choice for that kind of work. (But it will suffice if I don't change it) I would like to hone out the chokes to about 'skeet' and 'improved cylinder'. My first thought was a dozen or so slugs with valve grinding compound on them. But slugs are somewhat less than barrel diameter (nominal diameter is .729") So any of you Buckshot type gunsmiths have any other ideas, so I can do this without a lathe or other specialized tools?