I'm no expert, but I did sleep at a Holiday Inn last night...
I have read quite a bit about explosives but, unfortunately have never been able to apply that knowledge. So I'll give my rendition of what I've read We really need someone from Tannerite, or the like, to weigh in with actual experience.
All gun powders burn, rather than explode. They must be confined as in a gun barrel or other pressure vessel in order to create enough pressure to create a shock wave. You place a pile of smokeless or black powder on the ground apply fire and you get a "FFFFSSST", no "BOOM". You place a block of C4 on the ground and apply fire and you don't even get a "FFFFSSST", but you can make a nice cup of Joe with the resulting campfire. Take the same block of C4 and apply a whole bunch of energy at once, i.e. use a blasting cap, and you get a very satisfying "KA-BOOM".
The type of explosive determines the amount of energy required to initiate the "KA-BOOM". Nitro glycerin: very little energy (don't drop the bottle). C4, TNT, w/o the blasting cap all you have is another log on the fire.
As far a "high explosive" vs. "low explosive" I understand that has to due with the brisonance (sp?) i.e. how fast the explosive explodes.
As far as the muzzle flash goes I'm going say it's unburnt stuff, power or combustible gasses (I'm not sure), that, when they hit the atmosphere they find that last little bit of oxygen or time and finish the combustion process. I believe this is why a flash hider is is designed hold a large volume of gas and slow it down to allow the combustion process to finish before the unburnt cloud of stuff grows to the size of a volley ball. Where-as a compensator does not work as a flash hider because it is designed to redirect gas while it is still at high pressure and velocity therefor negating the slowing and pressure reduction of the flash hider.
What do you think? If there are any true "experts" I'd like to hear how close my version is to reality.
Kent