First, measure the bore of that gun with a caliper. You need to know the exact diameter to order the correct size wads. It can vary from 12 gauge( .729) to 10 gauge(.775). The nice thing about any ML shotgun is that you can always Load Them LIGHTER, by using less shot. With the cost of lead shot being what it is, that may be important, if you want to practice much. The Bess is not anyone's choice for a well balanced, wing shooting shotgun that I know about! :rotf:
You can start on the light side with a 2 3/4 dram powder charge( A dram is 27.5 grains), or 76 grains of FFg, and 1 1/8 Oz shot( If you are using an adjustable POWDER MEASURE, the 80 grain setting will give you about 1 1/8 oz of #8 shot) Velocity will be just under the speed of sound, 1062 fps, in the Hodgdon Reloading manual. The heaviest load listed for the 10 gauge is 4 1/2 drams( 124 grains) of FFg powder, and 1 1/2 oz of shot( 90 grain setting on your adjustable volume powder measure).( 1067 fps.) Keeping the velocity under 1135 fps is helpful in getting better patterns, when the barrel is not choked.
The 120 grain setting gives you 1 5/8 oz. of shot, and that is a lot of shove to your shoulder, particularly with that steel buttplate. Setting the powder measure at 124 grains would give you a tad more shot in the load.
Oh, the 76 grains setting will give you a little more than 1 oz of shot, and is more than adequate for game and targets out to 25 -30 yards, if you use the correct size shot for the game being hunted. I use #8 for dove, and clay target practice. I use #7 1/2 and #6 for rabbits, and squirrels when there are leaves on the trees. I use #5 for Pheasant and other birds, unless they are as small as a quail or dove, and then I return to using #8 shot. You can carry a bag or bottles of different size shot to the field with you, and make your adjustment on what you are hunting that day, or morning.
As to wads, I recommend you buy just Over Shot Cards, which are thin wafers about .010" thick, made of shirtback cardboard. Poke off-center holes in them with an awl, or other pointed instrument. In use, use 4 of them over the powder to seal the gases from the shot. After you pour down the shot, use 2 more OS cards to top the shot. This will insure that the shot load stays in place. Make sure as you put the cards in the barrel that you locate those holes so they don't line up together. To lubricate the bore, just carry a baggie with some pre-lubed cleaning patches, to run down the barrel After you seat the 2 OS cards on the shot. That will protect the barrel from rust during the hunt, allow the shot to slide over the barrel, rather than rub lead off on to the bore, and still soften the powder residue for easier cleaning.
The reason for using just the OS cards and not OP wads, cushion wads, and oS cards, is to simplify what you have to carry, and to use light weight wads that will quickly fall away from the shot column when they leave the barrel. The holes in the card allow wind to go through each hole and separate that card from the ones behind it. This helps to eliminate " donut-hole " patterns. Using the other combinations of wadding tends to create those donut hole patterns,as the heavier wads tend to follow the shot column after they leave the muzzle, bumping the back of the shot like a cue ball hitting the other balls on the break. Credit Jim Rackham for suggesting this OS-card-ONLY, loading technique, as a great solution to this problem.
I don't hunt with a Brown Bess, but I do hunt with both a 20 ga. Fowler, and a 12 ga. double barrel shotgun. With both, I carry a Range Rod for loading and cleaning, and do not use the Ramrod that came with the gun. In fact, I have removed the RR and the pipes from the DB shotgun, and the Fowler doesn't have a RR hole in the stock, or any pipes. I carry the rod behind by back, between my shoulders, , with the cleaning jag stuck under my belt, and the rod held to my back by the strap on my hunting bag. The handles stay above my head, which is no problem when hunting birds in open fields.
When walking through woods, I simply remove the Range Rod from my back and carry it along the barrel of the gun, held to the stock by my forehand. If a bird flushes( or the dog goes on point), I drop the the rod while I mount the gun, and cock the hammer. With only one shot, I stay where I am standing when the bird flushes, until after the shot, and I have reloaded the gun. No running around. I don't lose my rod, and frankly, its never been an issue. Considering the time it takes to reload any ML shotgun or fowler, If other birds flush, or the dog goes on point, there just is not much I can do until I am reloaded again, now, is there. :hmm:
Yes, you do miss some shooting opportunities hunting with ML shotguns, but you do get to see beautiful birds take to wing, and that is part of the enjoyment. If hunting was just about getting my daily bag limit, I would take my modern shotguns.
Because your Bess is not choked, its basically a 25-30 yard gun MAX! Don't be thinking about 40 and 50 yards shots, even with that large bore diameter. This is not a GOOSE gun, either, unless you can call them in very close.
Accept these limitations and then go out an have fun with the Bess and shooting shot loads. I will assure you that the first time you bag a squirrel, or rabbit, or pheasant with that gun, YOU will have earned a Trophy worry of a picture to be framed and shown to your friends. They won't believe you possibly shot anything with a Brown Bess. :hatsoff: