We are not fighting Indians, or fight in a war when we shoot MLers today. Because of that fact, SAFETY is the primary concern. Back in the day, if someone blew up his gun and was badly injured or killed, well, that was the breaks. It happened. People died from all kinds of things, including exploding gun barrels. In a war, or fight with Hostile Indians bent on killing him anyway, death was accepted, and the loss mourned. Accidental deaths were just part of the deal.
If you insist on being period correct, then make your vials out of wood, or bamboo( a grass). Both are historically accurate ways of carrying individual powder charges. You can wear period costumes, but don't expect anyone to be checking to see if you are wearing underwear or not. We really don't care, thank you! We don't expect you to walk 3 days to get from your home to the range, or come on horseback. You can, of course, but we can look the other way if you come in a car or truck! And, we won't laugh at you because you are using a steel barrel rather than a hand forged iron barrel on your rifle, either.Nothing we can do in the 21st century is going to ever EXACTLY replicate the experiences of living, hunting, and shooting, in the 18th or 19th centuries, or earlier. It can't be done. And if those folks who lived back then could come back to life now, they would not live that way again, EITHER!
So, please just be SAFE- First, last and always. This is a sport, and nothing more. I started out many years ago trying to acquire correct equipment. I was given some bad advice, unknowingly, because a lot has been learned since. I am sure that more information will come to light about what was " Correct " at the time in our future. But I did what I could with what was commonly know back in the 1970s. I made much of my own gear, to add authenticity. I learned to camp with less and less modern stuff and gear. I learned to cook over an open fire. I learned how to bathe, and shave in cold water! My percussion rifle was replaced with a flintlock. I had the DISEASE! I still do.
But, I used plastic cut-down, cigar tubes to carry individual powder charges into the field when I was deer hunting, or hunting Wild Boar. They were what I had available at the time, and they worked well. Someday I will get around to wooden tubes, I guess, with cork stoppers, or wood stoppers, but don't hold your breathe. Those plastic tubes still do the job for me. The best part about them is that I can carry them in a inside shirt pocket, and don't have to worry that my own sweat will foul the powder. That lets me leave my hunting bag at home, or in the car.