Heavily corroded M16A1

Yeah at that point it’s case by case that it has to be ruled, that STG receiver is honestly no more than scrap metal. The barrel might be an issue tho, usually in Europe once it has a chamber milled it becomes a regulated part, that’s why Lothar Walther sells us rifled blanks that we then cut the chambers in. You are correct, there’s a ton of guns still waiting to be discovered, here in Europe we get every condition possible, we even have laws that facilitate registering discovered guns. 90% it’s grandparents would hide all kind of stuff (MP40s, Mausers, etc anything) right after WW2 for fear the war started again. 50 years down the line the descendant find the guns in the walls when remodeling or the attics. I’ve seen everything from pristine 1911A1 pistols still in factory grease that were airdropped, to the extremely common captured MP40 and Mauser rifles in ~OKAY-ish condition and not really properly stored, to literal rotten pieces of wood because the guy died in a puddle and got buried under artillery fire. A hilarious listing I saw a few years ago: guy was selling a piece of wood that looked like tree bark. Literally a triangle of wood maybe the size of a forearm, he swore it was from a G98 WW1 rifle. Zooming in on the pictures he was right, you could notice the remains of a metallic disc, surrounded by rotten shit wood. Turns out it’s the stock unit disc on the butt stock of a WW1 Mauser lmao, he was really trying to sell what literally had become just rotten wood and rusted metal.