Bill: As far as I can tell, the oddball trigger is original to the Tobin. I first thought that there was a problem with it, so I took the gun apart to check it out. I had a drawing of the normal Tobin SST, and when comparing the actual gun to the drawing, it was obvious that the trigger was never machined or built to fire the left barrel, then the right, because the parts weren't there to do so. It has been several years since I looked at it, so I can't go into greater detail from memory.