I would have to concur with Drew above. If you measure the constriction of a full choke on an unmodified barrel and then measure the choke on a full choke insert the constriction is the same, roughly. I don't think that little thin walled insert will stop bulging. Perhaps if using a smaller shot size but I have never done that. I have Browning Citori's that have been set to modified in 3" chambers and I use #2 and BB Steel and have for more than 20 years in one of them with no problems. But I did have a stevens 311A with full chokes. One day while shooting and that was just before steel was mandatory, I ran out of shells and I asked my hunting partner to pass me a couple of shells in the heat of the moment. He was shooting steel shells in 2 3/4, BB, which I didn't realize till after the fact. Both my barrels budged. I only mention this because the wall thickness on the 311 was around .035.
