I recently conducted an experiment with some 5.56 steel cased rounds picked up at the range that were essentially gobs of rust; the headstamps were obliterated by rust. I pulled the bullets with pliers from four rounds. The powder in all four rounds was dry and loose, and burned when lit with a match. Three of the four primers fired when struck with a punch. That "steel cased crap" seems to handle dampness rather well.
I had some of the Pakistani (POF) .303 British that Steve mentioned that was prone to hangfire; I didn't have any that was prone to FTF. I pulled the bullets from a few unfired rounds from the same lot and reloaded the cordite and bullets into commercial cases with new primers. All of it fired normally with the new primers. When I popped the POF primers in the rifle before scrapping some fired normally but some made a fizzing sound.
I have fired thousands of rounds of Eastern European Soviet era 7.62x54 and 8x57 from the 50s through the 70s and I've never had a dud primer. I wouldn't hesitate to use recognized brands of European primers.
