I've tried searching for the article but it is probably too old to have been digitized. I remember in the early 60's reading an article in a gun magazine I can't remember the name of featuring a guy that made a single shot 50 BMG rifle. He used an M2 barrel but turned it down and shortened it to make it a bit lighter and fabricated a single shot bolt action receiver for it. In an effort to reduce felt recoil he designed a stock that utilized a shock absorber contraption that compressed when the rifle was fired. The barrel had no recoil compensator on it so it had quite a bit of recoil. The article had pictures of him shooting the rifle and the last picture was at the end of the recoil movement. The stock was collapsed to the limit and his right shoulder looked like it was dislocated. His face was almost kissing the barrel in front of the receiver. It had to feel like getting hit with the full swing of a 10lb sledge hammer. This same masochist had a 45-70 single action revolver built. He shot something like 25 rounds through it and it had worn out the palm of the leather glove he was wearing on his right hand. Seems like this guy specialized in outrageously powerful guns.