What happens is the primer gets dented (an ember lands in the pan), and it doesn't go off immediately. There are lots (for certain values of lots) of reasons this can happen. Mostly it's from a misplaced/aligned anvil (the structure in the case/primer which pinches the lead azide (the normal compound for primers, these days; replacing fulminate of mercury), which pinches the compound, but doesn't have enough between it, and the cup, to cause immediate detonation.
The other reason for it is a round which has a large space in the cartridge, and a small amount of powder (this isn't uncommon with 30-06, because modern powders have a lot more oomph. It's really a concern with things like 45-70, 30-50 and the like, because black powder [the source of the second number is how many grains of black powder the cartridge was designed to contain) is much larger, for effect, than modern smokeless powders.
When that happens (large space, small quantity of powder) the amount of powder the primer ignites can be small, or against just the surface (primers have a lot of energy, they will shoot sparks 8-18 inches past the muzzle) of the powder. That causes a delay in pressure build up.
I've had a few hangfires, none were longer than 1/3rd of a second.
no subject
What happens is the primer gets dented (an ember lands in the pan), and it doesn't go off immediately. There are lots (for certain values of lots) of reasons this can happen. Mostly it's from a misplaced/aligned anvil (the structure in the case/primer which pinches the lead azide (the normal compound for primers, these days; replacing fulminate of mercury), which pinches the compound, but doesn't have enough between it, and the cup, to cause immediate detonation.
The other reason for it is a round which has a large space in the cartridge, and a small amount of powder (this isn't uncommon with 30-06, because modern powders have a lot more oomph. It's really a concern with things like 45-70, 30-50 and the like, because black powder [the source of the second number is how many grains of black powder the cartridge was designed to contain) is much larger, for effect, than modern smokeless powders.
When that happens (large space, small quantity of powder) the amount of powder the primer ignites can be small, or against just the surface (primers have a lot of energy, they will shoot sparks 8-18 inches past the muzzle) of the powder. That causes a delay in pressure build up.
I've had a few hangfires, none were longer than 1/3rd of a second.
It was a long third of a second.
TK