This guy can be a little nerdy but he has some good info regardless. Only thing that scares me about stuff like your Winchester is I wouldn't know a fake from a tampon.
I just figuratively pulled the trigger on an original Win 1897 beater (so I can slam fire it) that has been refurbished into a period correct 1897 Trench gun. The same deal and company the the nerd in the trench gun youtube video above has. It's not an original trench gun mind you....but an original 1897 that has been made into a replica trench gun, sans bayonet.
