I had Briley thread a Spanish made double 10ga. in their pattern. Most 10ga. SxS's and singles don't have the barrel wall thickness for Invector or Rem choke. Briley is expensive but their workmanship is top notch. I had two extended tubes built by them in .705" for shooting #4 & #5 lead and two flush mount tubes in .725" for BB lead coyote loads. I didn't want Tru Choke threads because there are no options for doubles except .740'' full flush mount. Can't use Colony 10ga. turkey tubes in a SxS because because the OD of the extended part is too thick and extends over the other barrel. I still have my first dedicated turkey gun, a H&R 176 10ga. with a .740" fixed choke, that bought for $80 as a 16 year old back in '86. Had to have my mom buy it for the paper work purposes. I've been thinking about sending it to Briley and have it threaded since I can use the tubes from the SxS.