RE: roundball loads
Normally you will find the long rifles are excellent roundball shooters. Depending on the powder, sometimes a wad is needed. All you can do is try them with and without. I find that if I shoot a substitute powder, I get more control with a wad, but when shooting Pyrodex or Black powder, the wad really seems to make little difference. Still, try the rifle both ways.
I was told by an old muzzleloader shooter that they used use, cornmeal, bee hive, chunks of wool yarn, all sorts of things as a wad. I have made my own and now purchase them. Getting too lazy in my old life to sit and hammer them out. Although I still do once in a while for the fun of it.
As for the sprul or spur as some call it.. when you cast a roundball you will often times get that spur on the top from where the mold cuts the lead at the pour. I have found that if the home cast ball are consistent, it makes little difference in accuracy. Then there is the debate of spur up or down in the barrel. I like to put them up. Does it make a difference? I don't know but it makes me happy. At least I know where the thing is and I am consistent with the loading.
Another thing about long rifles, they can shoot real accurate with less powder. Some of them I have seen do very impressive shooting with only 50 grains of Goex. In long barrel rifles I like to shoot a 3f powder. I think the longer barrel is able to use the barrel pressure better. Pyrodex P is another good powder in the longer barrel rifles. Start shooting it once at 50 grains and see what happens. Also, never under estimate 50 grains of powder. I know a fellow that hunts deer with 50 grains and a roundball. He shoots a Lyman Great Plains Rifle in .50 caliber. His theory is he wants that ball to stay in the body cavity and release all its energy in there for shock factor. Whether that happens, I do not know. I am not a ballistics person. And his shots are all close. But he claims he still normally gets a pass through. Another friend of mine shoots a Tradition's Kentucky long rifle in .50 caliber and he loads 110 grains of Pyrodex RS. I watched him drop a big deer in its tracks at over 100 yards. That was an amazing shot. Whether it was luck or skill, I do not know, but to watch that deer fold at that distance from a simple roundball was amazing.