GOEX Powder
I recommend getting GOEX 3fg. The 3fg can be used for the main charge and for priming. It is almost as fast as 4fg. Most can't tell the difference in performance.
Powder Horn:
I would pass on a horn at this time since you are not intending to be period correct. You can get all the advantages of a horn with the the Knight flask and it comes with a measure. Unfortunately Track doesn't seem to carry this one.
Brass Black Powder Measure with Flask - Knight Rifles (knightoutdoors.com)
Priming Flask:
I like this one from Track as it is free flowing and you can use 3fg powder in it. Or if at some point in the future of course 4fg.
Flint priming flask, with free flow valve, brass - Track of the Wolf
Flints:
I use black English flints. In the special instructions on the order ask for flat on top and bottom. No humps.
Flint tools:
You will need a touch hole pick. A safety pin or paper clip of 1/16" or smaller will do. You will want a screwdriver to fit the bolts and screws on your rifle. Get two hollow ground screwdrivers that fit the lock bolts, and the jaw screw. You may want a small screwdriver to adjust the sights. The large screw driver can be used to knap the flint. Its too soon, but a spring vise will find a way into your tool kit eventually. A knapping nail or knapping awl can be made in a few minutes from a 16 penny nail by filing the tip flat then a notch in the flat tip. Use the handle of your screwdriver to tap the knapping awl.
Short Starter:
You will want a short starter.
Range Rod:
Loading, cleaning, and eventually ball pulling duties will be much easier with a good range rod. Track and October Country make good ones. The handle on a good range rod can be hooked over something to do the pulling. the rod pulling attachment is really not necessary.
Patches:
Getting your own patches from a fabric store is a good plan. Yes measure the material. Be aware that any indication of compressability in the store is obscured by the sizing in the fabric and actual measurements won't be valid until the material is washed and dried. I recommend # 40 cotton drill cloth from JoAnn's Fabrics. Its 0.018: thick and holds lubrication well. While at the store get some very cheap baby flannel or diaper flannel for cleaning patches.
Patch lubrication:
I'll go with the 1 part Ballistol and from4 to 7 parts water as the patch lubricant. I use it damp. Put it in your own bottle. For that matter patch lubricant that works can be most anything from spit to exotic blends of soaps, oils, rubbing alcohol and water or mink oil from Track of the Wolf for hunting
Gun Oil:
I use RIG as the grease for threads and parts that rub. I use WD-40 or rubbing alcohol as a water displacement in cleaning. I also use Ballistol after drying the water in cleaning as a penultimate cleaning step. For storage its a rust inhibiting lubricant such as Barricade.
Cleaner:
Black powder fouling is water soluble. The best cleaner is water with a few drops of dish washing soap if you use an oil based patch lubricant. I do use rubbing alcohol as the solvent for my wiping with a damp patch between shots. The Ballistol and water mix used for patch lube works too.
Possibles bag/ Shooting Pouch:
You want a bag just large enough to carry what you need for your shooting needs. There should be a few pockets to separate balls from patches and patch lube. Room to hold your flask with measure. A place for spare flints and a place for the vent pick and knapping tool and turn screw. I cut patches at the muzzle so a patch knife if good to have along. I often use a lock blade hunting knife that's razor sharp to cut the patches at the muzzle.
He said 54 caliber in the OP.
