The barrel and foreend - minus some shattered wood splinters - were found in one piece in front of the bench. The scope was bent and its mounts destroyed. The wood buttstock was shattered through the wrist. The action was catastrophically disassembled. The action of the rifle was peeled open like a banana. The trigger group was held in only by the rear pin. The bolt head was eventually found, with approximately half of each locking lug smeared off (this was the newer Remington Woodsmaster with four lugs, not the old nine lug artillery style lock-up). There was a fresh half inch by inch and a half hole in the plywood divider between the shooter and the fellow shooting next to him. Whatever punched the hole was not found; neither was any sign of the cartridge case head. The magazine was smashed and ejected from the action and the several of the unfired cartridges were knocked open. The remaining cartridges held the strongest clue for what had happened.
Initially the range officers thought rifle somehow fired out of battery, but as the broken open cartridges were being collected for photographs they noticed there appeared to be two kinds of powder lying on the bench. There were both small grained spherical pistol powder and the extruded grains of IMR 4831 rifle powder the shooter said he'd used to assemble the loads. He said he metered his charges into the pan and then trickled them to weight on a scale. At the time I left the speculation was that, as a handloader of both pistol and rifle cartridges, he had not completely emptied his meter of pistol powder before loading his rifle rounds. This was not authoritatively established. Maybe it was just an overcharge (or undercharge). Perhaps the rifle was out of battery when it was fired. We'll likely never know. I do know I've got even more respect for the 50,000 pounds per square inch operating pressures we handloaders and shooters manipulate at the loading bench and on the range.