Tested by inserting foam darts, the inner diameter of the Diamond Dogs barrel seems to be very close to Worker’s. So close that if I inserted a foam dart with my eyes closed, I could barely tell which brand it was.
The main visible difference is at the muzzle end. The Worker barrel has a nicely rounded edge, while this one is flat-cut, so it doesn’t look quite as refined.
1 × Diamond Dogs threaded-breech barrel 495mm