The factory used to drill and tap 410 barrels on special request. It used to cost around $40 including the base. I have had two done and have had a local gunsmith cut the choke off of both of them. I have had good luck with accuracy shooting brenekee slugs out of them. I last had the factory drill and tap a barrel about 2 years ago but with the changes I don't know if it is still an option.