Work on my gins - Chiappa Firearms 20GA .357 MAG/.38 SPL Colt Caliber Conversion Kit

I have these adapters in three different brands of break action shotguns a ATC 20 ga , a Rock Island Armory 12 ga and a Stoger 12 ga Coach Gun. They fit fine I think the trick is to use them on guns with either screw in chokes or nothing with a fixed barrel smaller than modified