Mike,some of us have taken these older guns with short chambers and opened them up to 2.750".It works nice to open the cones up also at the same time.You then will be able to shoot ammo available at your local stores.I do all of my 20 ga. and 16 ga. guns this way and they work fine for me. Best of luck and maybe we will see you at "The Southern Side by Side in a couple weeks.Charlie.