:v From personnal experience I can say that standing behind the firing line I can hear a delay between cap "crack" and muzzle "Boom" with just about anybody firing Pyrodex or 777. Pyrodex P is much faster but still not in the league with Bp for ignition speed. This is not to say that Pyro is bad it just is the nature of the beast. Bridging of the granules is certainly a problem in some guns. But one uses what they have and some have found ways to help with Pyrodex in thier guns.
If all that I could get to shoot was bar-b-que brickets I'd find a way to make it work. :v somehow. :v