I know this is about 45-70, but I feel the info I have about .45LC may apply to the old 45-70 as well.
After seeing detonation using Unique and 45 Long Colts I am sort of paranoid of making reduced loads using anything other than Trail Boss, or another high volumne powder. While we waited for the ambulance to carry the injured person to the hospital I picked up the unfired rounds that flew out of the exploded pistol. You could shake the round and tell there was not much powder in them. I read the label on the end of the box where the loader had written down the load. I cannot remember the weight of the cast bullet or the weight of the powder charge, but I do remember it was Unique powder because that was what I was using at the time in my .45 LC. And I do remember it was a lot less powder than I was using.
I was sitting at a bench facing towards the shooters to my left, talking to a friend. I watched this guy (found out later it was a young Army Troop) about 40 feet away lower the gun to his right side. Then slowly raise it to aim at a target that was slightly below him on the ground. Then he fired and the gun exploded.
During the investigation I was contacted as a witness to the accident. Had an Army weapons expert tell me about detanation in large capacity cartridges. When I explained what I had seen this troop do, the Expert called it a classic detonation scenerio. Powder was at the bullet end of the case. Primer fired in an empty air space between it and the powder. When the powder ignited it caused extreamely high pressure, more than the imported Colt .45 clone could handle. From that point on I always made sure I pointed my .45 at the sky before slowly lowering it to fire. And I quit using Unique, I use a higher volumne powder such as Blue Dot. Then Trail Boss came out.
