With the help of this youtube video from Keith H. Burgess (the Obi Wan of black powder), I put together a few cartridges for my 1777 Charleville.
My pal Wesley over at The Long Roll provided the location and additional assistance. Thanks Freems!
I tend to over accessorize
My stocked “Lafayette” cartridge box.
Overall, pretty simple to do. I used a brown bag for material, but I’m afraid this may be too tough to bite through.
Muskets may not be a precision instrument, but the act of loading and firing them while in the heat of battle definitely is. One could only imagine the nerve it takes to break open a cartridge with your teeth, prime the pan, then pore the remaining powder and ball into the barrel while under fire. I think it would be difficult to avoid pouring the powder all over the place while priming the pan.
This guy does it rather quickly. I wonder how fast he would be if he were being shot at?
Update
Since this post I’ve updated my cartridge making technique thanks to some YouTube videos similar to the one Bill posted below in the comments. MUCH better!
Cartridge Box Improved!
Twistification 
The six holes in the middle of the French Grenadier box are not for cartridges. They are for other things. The cartridges would go into the two square box areas on either end.
Wow, those holes fit the cartridges perfectly! I can place them where I know which sides are up (so I don’t bite off the wrong end)! Do you know of any examples of something they would put in the holes? Ball? Paper?
For cartridge making (sorry, don’t know if I posted these before), also check out:
http://www.youtube.com/watch?v=AYUPaX-F_nA and
Thanks Bill! I need to update this page since I did come across a youtube video similar to this that improved my technique. The consistency of the cartridges has done miracles for my accuracy.
The only difference I see is that I use a template to cut out the paper (Wal Mart packing paper which is perfect) and I cheat a little and use some kids glue (I think I would use wax if I wanted to be more authentic).
I also made a few buck and ball cartridges this weekend that worked GREAT.
4WIW, here’s another cartridge-making link, this one including ball, supposedly according to authorized Rev War instructions: https://www.youtube.com/watch?v=AYUPaX-F_nA
Don’t twist them closed.
Instead, fold them closed, leaving enough paper above the powder charge to easily bite/tear through.