Ah, the good old days. I recall back in 1959 when I was in high school, I found a junkyard with a lot of cut-up .50 BMGs, and I bought a couple to play with. When I got home with them, a neighbor, WWII vet, saw me trying to take one of them apart, walked over, and showed me the correct way to disassemble a .50HB. We worked on that gun several days, removed everything, cleaned up all the parts and ground smooth the cut in the side plate, and reassembled it.
Well, at one point a couple of years later (This is all pre-1968 amnesty, OK?) I took a welding class and decided to weld up the gun and see if it would function. Did that, ground off the extra material, cold blued the weld, and got the gun into working condition and took it out to the sand pit one weekend with my dad and shot it. I registered that gun during the '68 amnesty. That really got me interested in automatic weapons, and I'm still collecting them.
I wonder if any of that would/could happen these days?