I'm just reading in P. O. Ackley's Pocket Reloaders Manual about a dangerous condition being created if a bullet is so loosely seated in a case neck that somehow before firing it actually slips back into the case. Quoting P.O.: "This creates an extremely dangerous condition when the cartridge is fired. A number of blowups have been brought to the writer's attention during the last year or so, which were apparently due to this condition."

Is this true? Would this cause a gun to "blow-up"? Why? How are we defining "blow-up" - destruction of the action or just a bad gas leak (probably depends on the gun & load)?

I wonder - how did P. O. possibly determine this to be the cause? Could he magically see inside the gun before the trigger was pulled? How could chambering a round force the bullet back into the case - especially with the usual case full of powder? How could a reloader/shooter be so dumb and/or careless? I know this last question will be hard to address since there are NO dumb or careless reloaders on these forums!

[ 12-31-2002, 00:12: Message edited by: sonofagun ]

The physics is that pressure is inversely related to the volume of the space - burn the same amount of powder into a hot gas in half the space and you just doubled the pressure. This usually can't happen in a rifle case for the reason you mention - the powder fills the case and the bullet can't be moved back. But if you use a "light load" for practice or just plinking for lighter recoil then the powder isn't filling the case and the bullet can get pushed into the case. And of course for some cartridges like the 45-70 and the heavy african cartridges like the 450, 470 and 500 Nitro Expresses or equivilent then the powder charges do leave air space - sometimes considerable amounts of empty space in the cartridge. This is much more common in pistol cartridges - I've read that the old 38 Special target load of 148 grain wadcutter over 2.7 grains of Bullseye doubles the pressure generated when the bullet gets pushed into the case by just 1/8" of an inch. This is from articles about the "detonation" vs double-charged cases investigations when revolvers were blownup by these light loads.

The cases you mention (especially all pistol cases) are straight sided. Ackley's comments are specifically about bottle-neck cases (with "extremely short necks") that are resized improperly (loose bullet fit). See page 10 of his manual. Sorry for not mentioning this in my first posting.

[ 12-31-2002, 01:34: Message edited by: sonofagun ]