The paper cartridge was developed to make loading faster and easier.  The musket was loaded from a standing position.  The soldier bit off the tail of the cartridge and poured a small quantity of powder into the pan which he then closed.  The remaining charge was poured down the barrel and the ball dropped in and rammed down on top of it with the ramrod.  The ball could be loaded with or without its paper covering,  depending on how fouled the bore was with the black powder residue.  If the ball was loaded without the covering, the cartridge paper could be rammed on top of it to keep it from working away from the powder or rolling back out the muzzle.  When the musket was fired, some of the gases escaped around the ball which was smaller than the barrel diameter.  The ball tended to bounce from one side of the bore to the other until it exited the muzzle, which resulted in poor accuracy. 

The buck and ball cartridge contained a .69 caliber ball with three .31 caliber shot loaded on top.  A string formed half hitches between the projectiles and below the large ball.  The buck and ball load was always loaded with the paper covering since the string ties were intended to keep the shot and ball together until out of the muzzle.  The photo on the right shows a .58 caliber minie bullet seated on top of the powder charge.