In the pre-flintlock era, before the invention of paper cartridges, it became common for musketeers to carry pre-measured powder charges in wooden bottles hanging from a bandoleer. They have come to be known as the "12 apostles," after the Apostles of Jesus. (In my quick research, the term may actually be more modern and not in use in the 17th Century. Regardless, it's in use today.)
Regardless, many modern muzzleloading shooters like to pre-measure their powder charges before heading afield or to the shooting range. There are numerous "quick loaders" available from the usual black powder shooting suppliers, but I found a cheaper alternative:
The modern apostles in the picture are 10ml centrifuge sample tubes with snap caps. Each has 70 grains of Goex FFg black powder in them, which occupies about 5.5ml. So, there is plenty of space in them for hunting loads in my rifles, which will be under 100 grains. I bought a bag of 50 of the tubes from Amazon for $10.39 on Prime. 15ml tubes should handle hunting loads for almost any muzzleloader.