how far bullet has moved before that granule ignites and upon how
fast that granule subsequently burns, which depends upon granule characteristics
and local pressure). In some circumstances, such granules can reduce
bullet muzzle energy because energy used to accelerate and heat said
granules exceeds energy said granules can contribute to bullet!
5.
Tertiary Ignition: Granules that primer plume does not heat sufficiently
on any portion of surface to achieve ignition but which are subsequently
heated sufficiently by nascent granule combustion to begin burning
but only after bullet has moved more than perhaps 15% of distance
to muzzle, such granules cannot contribute significantly to bullet
acceleration because too little time exists for such granules to generate
significant gases and because any such generated gases have too little
time to work on bullet before it exits muzzle. Such granules almost
certainly result in a loss of muzzle velocity, as described under
heading 4, above.
6. Non-Ignition: Granules reaching muzzle before
igniting. Such granules generate no gas to work on bullet and significantly
reduce energy that can work on bullet, as described under heading
4, above.
With regard to item 1, above: It is important to recognize that smokeless propellant granules are generally extremely tough plastic objects that will normally tolerate surprisingly violent abuse – if this were untrue, internal ballistics would be an entirely different science! Hence, despite brisance of primer plume, as produced from flash hole, under normal circumstances, this jet pulverizes very few, if any, granules and it cannot simply bore a hole significantly far