"BB's showed a 1/3 misfire rate for the flintlock BB'
That is interesting, 1/3 failure sounds very high for a well maintained BB, I would be curious as to the accuracy of this source myself???? as mantioned in the past the typical method was to use the same powder and it was probably somewhere between put 2f and 3f definately not the standard of screening we go by today, the larger sparky locks with adequate period size vents work well with the same powder for prime as main charge.We do many things quiote different today by the standards of the past, small vents, smaller locks at times, heavier charges, tighter P&B combos.