Yeah it does say lead shot only, but it was made before heavy shot was even around and I think they are refering to No Steel shot . Heavy shot , I believe supposed to be safe in most all chokes. I used to shoot a 2.25 oz. of lead #6's and I think a 1.75 oz. load of Hevi would probably be safe. Hastings made chokes you could buy for around $25 a piece 17-4 steel I believe. The 10 ga offerings went from .675 - .700 If I remember correctly. I have a Hastings .650 that patterns good with the Old Federal premium 2 oz.#5's for a Rem 12ga. That was back when you could kill Turkeys with Lead.