probably drifting off topic but if i remember correctly what canfield wrote in his book on martial shotguns, the military felt the 31 held up the best in combat of any pump used in wwii and the model 12 was a close second. i've only owned one 31 and have to admit i liked it a lot, particularly that wide open unimpeded loading port.
i've never owned a 51 but a buddy did. had some problem with it he never could get corrected. but again if i remember right, brister wrote that it was the best gas auto at the time. i never wanted one because of the aforementioned problem.
roger
