Like I said, it's unique. It was also the gun that introduced Speed Load. The first shell in the loading port gets whisked into the chamber and the bolt slams closed, ready to fire. Early guns had steel receivers but most have aluminum-- anodized in different colors, Forest Green being one. The silver gun is mine, currently at Art's having the stock re-done.
1955 - 71. Not sure when mine was made, I dropped it off at Art's shortly after I got it. http://www.browning.com/support/date-your-firearm/double-automatic-shotgun.html
I think that was the idea. But it's a light gun with a slim fore end, and it loads fast -- once you get used to doing it left handed. I think a lot of guys use theirs for hunting.
Had my '57 DA out on Saturday evening one of my three. Bagged a couple of Ruffies with it. Steel reciever model with a Cutts Comp sitting at the muzzle end.
Well, along those lines, there also is not a section for that Browning "recoiless" 12 gauge I mentioned a few months ago. I forget its actual name. Maybe we need a "none-of-the-above" section.