i am not sure if this is the right place or not. so if not, please move it. anyway, i have been loading for quite a while. looked at many books on reloading. i guess i only partially understand the "burn rate" thing. i get how different powders burn at a different speed. but being a lifelong mechanic, i tend to view things as they happen inside of an internal combustion engine. in regards to gun powder, in my brain, this equates to fuel/air mix in the combustion chamber. obviously the biggest difference is that in a combustion chamber, there is a considerable amount of room for gasses to compress. inside of a rifle, pistol, or muzzle loader, there is little to none. that is where things get "fuzzy" for me. in slower rifle powders, the bullet moves down the barrel as the powder is still burning and gaining pressure. but i am not sure of where peak mean useable pressures occur (1/16th down the barrel, 1/4 way??) . and in muzzle loaders, with either real b.p. or substitutes and many pistols, everything happens at a much faster pace. i THINK that the bullet HAS to move somewhat as the quick powder burns, if it did not, i would think that the pressures would rise so rapidly, the gun would simply become a pipe bomb. in rifles all of this makes a certain amount of sense, pistols do the same thing only much quicker, as evidenced by the burning powder creating the flash towards dusk. black powder. i guess it the one that is the least understood by me. it can be an explosive, or a gun powder. which confuses me. in my mind, an explosive detonates, not burns. but if it detonates in a barrel, the gun should become a pipe bomb, unless the steel is extremely thick and can contain all that pressure. a cannon would be a good example of this. but in a rifle or pistol, the walls do not seem thick enough to contain a detonation. can somebody please clear this up for me?