well, if you want to be correct in the military loading here is a quote, now the powder may have been of lower quality than today, and you would surely not want to pour this much down the barrel, but, read this quote, and see what you think before you call 100 grains the standard charge...
Shortly before the beginning of the war, orders were given that cartridges should be made using less powder than previously for Brown Bess in the British army:
"General after orders 21st Novr. [1774]
The Regiments will observe in firing at marks that the quantity of powder necessary for each cartridge (as it has been found upon many trials) that forty or forty- two Cartridges to a pound of powder will carry a ball truer than thirty two Cartridges, which is the number usualy made up with a pound of powder."
The reasoning seems sound, but some officers were skeptical of the decision:
"Yesterday was given out an Order to the Corps in Garrison, that when they fire with Ball they are to use Cartridges 42 in the pound, as they are found to throw a Ball with more justness and to do equal execution with those of 32 to the pound. By whose experiment has this been proved?"
42 cartridges to the pound would work out to 167 grains per cartridge. And the previous loadings were at 32 cartridges to the pound, or a little more than 218 grains each.