Flame temperature might be the same but where is it applied and how fast? I am sure a pile of FFFFG BP has the same temps as cartridge but I assure you FFFFG is not where you want it in a rifle.
Powders have a suppressant coating to slow burn rates from one piece of powder to another to extend distance. The coating must be breached for flame to enter. Most powders are exactly the same formulation and only the coating and shape, size of grains changes the burn rate.
I think Lil'Gun has a different formulation where the coating has changed. There must be a flash over. It might not burn hotter but where is the heat in relation to your steel?
