I made a .22 caliber muzzle loader from an old .22 RF barrel. I use air gun slugs with 5 grains of 4f for dime sized groups at 25 yards. You might want to look at the AVS air gun site to see if they have a projectile that will work for you. I went with the slugs because I could not handle those tiny lead balls and patch very well with my sausage fingers.