The patching material is the key to be accurate with a round ball load. A good patch is made of good quality, dense natural material. You can buy good quality patches in your local blackpowder shop, but you can also make your own. Which ever you choose, keep in mind a few things:
You must have a tight patch-ball combination
It is easy to determinate the minimum thickness of the material: If your bore measures .50” between the lands, and your ball measures .49” the difference is .01”. This leaves .005” on both sides of the bullet. This seems to be your minimal patch thickness, but in fact it is not. The patching material must make a gas tight seal, so you need to fill the grooves as well with your patch. S add the depth of the grooves as well, and there you go, you have something to start with. In this case the right thickness should be around .014-.016”.
Lubricate you patches. If you are using clean burning powders like the Swiss, the good old spit-patch will work. If you use one of the dirtier powders melt 1 parts of beeswax and 8 parts of tallow in a pot. Dip your patches and let them cool.
Choose the right patch size that can cover your ball completely.
- Learn to read your patches. Collect them after they are shot. A gas tight seal is indicated with a complete circle of blackpowder residue drawing also the from of the grooves. The edges of the patch must not disintegrate too much, and it must not tear or perforate.
To decide weather you can shoot roundballs from your rifle accurately or not you have to know the rifle twist of the bore. This number gives you the distance where the spiral of the grooves makes one complete turn. The faster your twist is, the better it is for conicals. You can shoot roundballs from a fast twist barrel, but you will have to reduce the powder load dramatically or the ball will simply jump the rifling without turning with the spiral. Knowing the rate of twist is important, but often not enough. You must check your rifling profile as well. The gunsmithes of old times knew what the differences were: the patch round ball riflings were deeper, and the edges of the lands were rounded to save the patch from cutting. The number of grooves was also greater than the riflings for conical bullets.
Roundballs are versatile projectiles, they are capable of remarkable accuracy. The will work well for target shooting and hunting. But if you plan to hunt, don’t forget to limit your range to maximum 50 meters.