I had a 16 Sterlingworth with chambers ruined by two paper shells left in the chambers for several decades in a very wet climate. Having other 16's the only way to justify chamber sleeving was to go down to a 20. I could have found a set of donor barrels for less effort and money. But I wanted a long barrel 20 and went with a 20 ga. chamber sleeve to make a set of 20/16 over bored barrels. I figured that it would become long range death to all the doves. Funny they seem to fly around my patterns too often. Not the fault of the gun I am sure. I am sure you could have your gun sleeved if you want to keep it as a 12.
