i carry some pre-loaded containers with the bullet and powder in them along with a little brass dispenser of 4f in a lanyard around my neck. i don't carry any other powder because i figure if i can't get one in 5 or 6 shots i carry preloaded then i need to quit for the day. one of the most important things is a touch hole pick. in this season you need to dump your pan powder and pick the touch hole a lot. i also carry a screw driver and breech plug wrench so i can completely disassemble the gun if it gets plugged or drenched. i also have an extra flint too and obviously a bullet starter too. i hunt with powerbelts so i'm not really that traditional and i don't do the possibles bag. all my stuff fits in the pocket of my game bag in a ziplock gallon bag. i'll bet jeremiah johnson wished he had a few of those.
Wire brush jag and some cleaning patches. Rags/paper towels, keep in a plastic bag to KEEP DRY! Nipple pick. Small screw driver or multi-tool to take apart gun/lock etc. Few spare flints never hurts...
In my bag I have,
6 premeasured charges
small leather bag of RB's
RB starter with pick in end
Film canister with patches
container with extra flint,leather,clean patches,patch worm,screwdriver,jag,and short toothbrush for cleaning pan.
I carry very little.I take 5 pre-measured charges.One extra flint,a multi-tool,dry patches and pan charger.My ramrod has a brass jag on it and I zip tie a brass touch hole pick to my sling.I've never needed anything else.
It depends on the weather.I keep only one extra ball,patch,measured load.Primer,ball starter,alcohol soaked tissues or moth balls in a sealed zip lock bag,toothpicks,couple small rags like washcloths.If bad weather then carry a towel also.I have a possibles bag that I got with a double flinty buy several years ago but never used it.Just put stuff in my pockets.
Well I take my possibles bag, and if you went through it, you'd see I pretty much have everything you could think of, except for an extre ramrod. However, I have enough tools to probable make one in the field if I needed to.
loading block with 3 balls and patches around my neck, my powder horn that i have had for 30 years, a small leather bag in my pocket with extra flints, screw driver, pick, knapping hammer, balls, patches(lubed), ball puller, wire brush. brass primer on lace in my upper coat pocket.
I'll swap out some of this stuff depending on gun and use, but my bag holds cleaning patches, vent pick & brush, musket tool, CO2 ball discharger and leather pouch with CO2 cartridges, shot pouch, brass priming powder tube, brass powder measure, pliers, screwdriver, leather ball bag for .45 cal balls, leather flint pouch, tin for wads and cards, wooden ball starter, goatskin leather roll with various tools, tin for ball patches, frizzen stall, spare vent pick for pocket, and larger .62 cal balls
I'm actually making a slightly larger bag now to hold a few more general hunting "possibles".
I usually carry about 5 speed loaders; a real small plastic box has an extra flint,leather,patent breech brush,a patch puller and a small tool that fits the hole on the jaw screw for changing a flint; a pan charger, short starter that has a long enough shaft to push out the speed loaders and no longer, the ball of it also has a hole drilled in it that fits over the ramrod to push the load down; a sandwich bag with clean patches and a small squeeze dropper bottle of solvent. My ramrods are short enough to leave the cleaning jag on it and still be able to swab the bore. I also carry folded up waterproof lock cover and a small ziplock bag with rubber gloves,twist ties,and some paper towels for cleaning the kill. I always have a small handtowel to keep stuff dry. I usually have a couple pieces of duct tape on the stock for putting over the muzzle on wet days.
I just carry the essentials with me; I don't carry a pouch but I do keep one in the truck with backup stuff.