Also, a lot of people shoot the Remington factory turkey choke with tss which may be what you have. I tried a buddy's in my gun when pattering and shot well. You don't have to choke tss as much as lead.
Another good cheap, choke which my gun liked the best is a Carlson's 575. Good luck with what you decide but be careful as you might have to switch to a 20 ga yourself if you haven't already.