The article reasonably showed it was entirely due to accidental double-charges, but unfortunately the conclusion was transferred to the supposition that rifle detonation was also due to double charge. 38 Special wadcutter was a form of detonation. There was some further confusion created by a magazine article several years back that analyzed the claim that "Bullseye surprise" in the. The exact circumstances of detonation have never been reliably replicated in a laboratory and one might speculate that the powder has to be distributed in the case just right for some to burn and some to miss the primer ignition flame and get fused, or perhaps vaporized by the heat into constituent gases so that a heat-triggered gas detonation, like engine knocking, occurs? Unless a means of replicating the result can be found, speculation and the very occasional burst rifle are all we have to go by. It may also be the case that a powder that is harder to ignite is more prone to the problem for several reasons. The notion that only a slow powder can exhibit the problem may have arisen only because the phenomenon was first noted and published when 4831 was involved. The bursting loads occurred when that powder was worked down to very small quantities in large capacity cases, like the small charge of N320, described above. Click to expand.I understand that when "detonation" of rifle powder first was described in magazine articles, almost every rifle cartridge reloader on the planet was working with surplus IMR 4831.