I believe that sumtoy only does tru-choke in the 20 ga because that is the only tooling he has for a 20 ga. Yes there are plenty of chokes for tru-choke in 20 ga. Carlsons, trulock, colonial arms, and remington even made them @ 1 time. And i believe kicks,indian creek,pure gold,and sumtoy will make turkey chokes in that thread style. Hard to beat sumtoy's price for that service but do a search on Mike Orlean. He offers that service in tru-choke,rem choke,and invector style in 20 ga. All depends on outer diameter of the muzzle end of your barrel. I'm in the middle of a 20 ga build myself so iv'e done plenty of research on the subject. IMO send it to sumtoy and get one of his chokes with it and you will have 1 mean 20 ga.