Just speculating here, but to injure both hands, I doubt he was working the press. My first reaction was he was pouring primers into the tube and one detonated. We also don't know how old they were. I've seen some lately being sold as "old new stock" and I wouldn't take them even for free. I have a friend who was cleaning out her Dad's home after he passed away. She called me after opening an old cabinet in the basement with several boxes of very old, and leaking, primers. I had her call the sheriff. The first deputy giggled at her until he looked for himself, then he called the bomb squad. They in turn. giggled at the deputy before looking, then he went back and fully suited up. I won't say why I know about contact explosives, but they can detonate under their own weight, and from the picture it appears everything in the tubes went off. He's very lucky.
