Seating the bullet deeper causes an increase in pressure. It doesn't take much to make a safe load into a Kaboom. Ask any old reloader about it, it is one of the first things you need to learn to roll your own.
to deep, and
Okay, let me show my ignorance of guns and ammo.
I was under the assumption that older, black-powder guns had a slow rate of powder burn, so slow in fact that some residue of the charge was still burning as the round left the barrell.
Now, newer guns use much faster powder.
I would be surprised if powder was still burning, TO THE POINT OF INCREASING MUZZLE PRESSURE, when the round left the end of the gun.
I'va always assumed that maximum muzzle pressure behind he round was acheived early in the bullet's travel down the barrel. Is that wrong?
Ideally, where in the bullet's travel down the barrell is maximum muzzle pressure achieved?
I don't understand how the relatively short distance that the extra-insertion of a round into the casing experienced could account for THAT much overpressure. Once the powder starts burning and casing pressure starts rising, the bullet begins to leave the casing. As the distance increases, more powder has to burn to keep increasing pressure.
In my admittedly shallow bit of knowledge on guns and ammo, I would have thought that maximum pressure would be achieved several inches down the barrell, not at the point where the powder first began to burn.
It almost sound like the bullet is getting stuck in the casing and will not expel properly from the casing.