Winchester Prototype .410 Slide Action Shotgun
Winchester Prototype Shotgun 30-30 |
Winchester built this prototype bolt action shotgun in 20 gauge in 1919
Remington Model 11 “short pattern” trench gun prototype
Japan Low Br Shotgun 
Walther toggle-locked semi automatic shotgun
Sjögren shotgun
Italian Cosmi
DEFOURNY OF BELGIUM
ALOFS MFG. CO. RELOADING/SPEEDLOADER ATTACHMENT
Einhorn Revolving Shotgun
Type murata shotgun.
https://forum.enlisted.net/en/t/japanese-shotguns/141499/2y Frolov Shotgun
These bolt-action shotguns, nicknamed “Frolovka” , are conversions of Mosin Nagant rifles into hunting shotguns, designed by engineer Pyotr Nikolaevich Frolov and manufactured in the 1920’s at TOZ. A surplus of Mosin Nagant rifles, most heavily battered during World War I and the Russian Civil War, were converted into 20 - 32 gauge shotguns. Such a measure allowed to quickly cover the lack of cheap hunting shotguns in Soviet Russia.
Winchester Model 1887
Another of John Browning’s famous designs, this shotgun was first developed in 1887 by demand of a repeating shotgun for lawmen and cowboys to use.
Since the Soviet Union already has lever-action rifles, this should also exist.More Shotguns 
![Lot - W.W. GREENER SINGLE SHOT POLICE SHOTGUN, 14 gauge]
(https://auctions.morphyauctions.com/ItemImages/000527/22180121_1_lg.jpeg) 
You’re kidding. I thought it’s just fantasy stuff but not.
Make it hit as big as the japanese AT rifle and I’ll love it. 
