You can shoot the old style, foster-type, "rifled" slugs through any choke. Try the Brennecke slugs. They are the standard for accuracy through most smoothbore guns. In my BPS, with an IC choke in, I can get 4" groups at 100 yd. with them. Definately try the 2 3/4" versions. They kick less and quite often are more accurate than 3".