1. Have to admit I've never been there personally. I've heard people, real people, who have no reason to disinform, complain about the problem, and other people, who witnessed it, confirm the cases. The cases involve tightly choked guns, slugs fired without checking out if they fit the chokes, and the loss of efficiency happened with a very limited number of shells fired, resulting in both density and evenness loss. The hunter would finish the bird season with the gun and everything's fine, then take the gun for its first big-game season, and everything's fine too, than come the next bird season and the hunter realizes he can't hit anything with the gun at long ranges any more. Might be something psychological, might be an old wives tale, wouldn't bet my bottom dollar on that, but the folks who taught me shotgunning warned me about this potential problem, and I'm passing the warning. Edit: the warning didn't imply that every choke will be damaged by any slug, just that it can happen if one is doesn't know what one is doing.
Do you really believe that? Me not. When people talk about long distance shooting effectiveness I make a face, that I hear very carefully
Personally I try DO NOT shoot slugs through full chokes, anyway lead allow slug will be deformed through these chokes and accuracy will be poor. I prefer improved cylinder.
All cases with slugs I heard were associated with home made and reloded slugs. I could talk probably dozen of stories about human stupidity.
I believe I've never shoot round balls as using round balls at hunting is illegal here. Its dangerous, too much recochet.
