Dr. Kel has a French protorifle from World War 1 now. Yes, you can craft it in Story Mode. No, I will not tell you how. (Only hint is: It involves the Old Rifle somehow.) Enjoy. Credit to TastyTony on sketchfab.com for the 'Low-Poly Chauchat' model.
Dr. Kel is now able to stack as many backpacks onto his frail pasty enby twink body as you please. For the hoarders among us.