Tacome1942 is a genius. He makes working replicas of firearms, out of paper by hand. The use of metal is unavoidable. He does use metal for extractors, springs, firing pins, and screws. Now when I say “working replicas” they don’t fire conventional bullets. The paper barrels can’t sustain that amount of pressure. So what does he use instead? He makes his own bullets using match heads instead of gun powder. So they are technically working firearms with projectiles.
He has made a MG42, 1911, Makarov, AK47, and a Winchester 1894 just to name a few.
Check out his page to see his creations.
Just check out this revolver trigger mechanism he made, out of paper.