I don't know how I got in this mode. I had the top barrel on a Remington 32 blowup. I think there was a powder detonation. I was shooting the low house on Station 3 at skeet. The shell had been recently reloaded. I think there was a short drop of powder and then the loader did not full seat the wad, leaving an air space. The excess air provided oxygen for a detonation. Thee was not an excessive recoil, in fact, I remember no recoil. I still have the barrels and the shell casing.