nothing, you will have to shoot thousands of rounds to have any effect on it, as time goes by it just opens the choke up from its original diameter, it is safe to use the hevy through lead unless you do ALOT of shooting
I shot a few Hevi-13 3.5" loads through a H.S. Undertaker lead only choke and didn't have one bit of trouble. All these new Hevi-Shot choke tubes are nothing more than a marketing ploy to get hunters to buy a new choke. Most of the new Hevi-Shot chokes are made with the exact same type of steel as the lead chokes were made from. All they really did on these Hevi-Shot approved chokes was open up the constriction by .010 to make the chokes shoot the shot better with better overall patterns typically. Case in point the old Rem Super Full lead shot only was .665 in constriction. When they made the newer Rem Hevi-Shot choke, as far as I know the same type of steel was used but they opened up the constriction to .675 to allow the choke to shoot the Hevi-13 loads better. But that is not saying that a .665 choke can't shoot the Hevi-13 loads well. It all depends on your barrel and the size of the backbore for the most part.
