The Winchester Model 1897 is a pump-action shotgun chambered in 12 gauge and 16 gauge. Winchester named the 1897 after the year they introduced it. Although it was an advanced system for its time, its biggest feature is something that today’s shooters accept as the norm. It has a takedown design meaning the barrel can be removed. Otherwise it has a single action bar, so 1 bar guides the pump back (today it’s usually 2), an external hammer and a tubular magazine.
The 1897 proved to be a dangerous weapon in the trenches of the European battlefield during WWI because it had the ability to slam fire, so the shooter could hold down the trigger and pump and at the end of each pump a shot would fire.