I've run into some dirty stuff(reloads), and also a much higher # of failure to feed, and failure to fires then comparable factory loads, but the price differance usally makes it worth while, if I can buy 1000 rounds for about the price of 800, and 8-10 are bad, i'm still 190 rounds ahead.
I use some stuff from http://www.ammodirect.com/ , the l... than I can stand for from a new ammo.
Scott