"Can't these goofy rings be removed by cleaning? (ie. breech scraper, worm, and bore brush) Also, if you use soft lead (and inspect your ammunition) shouldn't you be able to avoid the problem altogether?"
In brief and to over-generalize...
The common cause for lead rings and fragments comes from poorly cast Minies. This is caused by the mold being too cold, or the lead being to cold so that when it is poured into the mold it does not flow and enter the mold as a complete liquid. Instead, teh stream of lead cools and hardens which creates a segmented "ripple" or layer effect in what is supposed to be a solid projectile.
The greatest weak area for a ring or segment to be torn from the Minie ball is the thin skirt area.
Being "behind" the mass/bulk of the bullet, the segment or fragment can be blown backwards toward the breech and NOT exit the muzzle.
"Cleaning" with a patch covered jag or tow covered wiper can simply push the lead bits down to the bottom of the barrel and not remove them.
This is a potential serious problem for lads who shoot the same gun (or barrel) for live fire as well as reenacting.
Many lads "dabble" in live fire and do not have the supervision or the experience in casting bullets to inspect and reject rippled or flawed castings. Plus, many dabblers buy commercially cast Minies which can have a reputation for being poorly cast.
In gleichem Schritt und Tritt, Curt Schmidt
Not a real Civil War reenactor, I only portray one on boards and fora.
I do not portray a Civil War soldier, I merely interpret one.