The belted ball is one of those concepts where the theory and practice debate can really get going. In theory, the belted ball will engage the rifling, and a lubricated patch is not needed since the spin is imparted to the ball by the engraving of the lands on the belt. In addition, reloading the belted ball is faster than loading a patched round ball. In practice, fouling builds up quicker, the barrel is not leaded up since the lubricated patch separates the ball from the lands. A round ball with the sprue flattened does not require alignment as it is loaded. A lubricated patch will wipe fouling from the grooves so more shots can be fired before fouling builds up such that loading is difficult. A belted ball can encounter enough fouling shut that the belted ball will get stuck in the bore. I have had similar problems when I used unlubricated paper cartridges and after about five shots the fouling in my Bess was enough that it was difficult to ram a paper wrapped 0.715" ball down my 0.780" bore.
There is a reason why belted balls are not seen while conical bullets that engrave on the lands are sold.
