I had the occasional reject cartridge with Turkish 8x57mm ammo. ...Be it bad primers, moisture getting into the powder through cracked necks, or oily powder.
With Wolf 7.62x39mm, I ran into a failure to fire in 500-1,000 rounds, with the early production ammo. As it became more "standard", stocked everywhere, more commercialized, lower quality, and more watered down, that failure rate kept climbing until it was about 1 failure per 150-200 rounds.
--In contrast, I NEVER had a failure of any kind with the true Russian surplus ammo that we were able to get in the early- and mid-'90s. (Referred to as "Gulag ammo" in my family.
) That stuff was fantastic. It smelled like a broken truck stop toilet, but ran GREAT and was very consistent.
Since then, I've had two failures of Winchester .30-30 factory ammo. It was of recent production (at the time), but not purchased by me. I suspect that storage conditions may have been a wooden box in the uncovered bed of the original purchaser's truck.... (seriously - the guy was a moron and that's how he stored the rest of his ammo, so it's not difficult to connect some dots and make assumptions...).
I have had multiple failures of Federal .243 Win, .270 Win, and 8x57mm. --Not just failures to fire, but truly dangerous head space issues.
And, on the reloading side, I had a bunch of .243 Win hang-fire on me, a few years ago. It was, however, loaded in 1962 and stored in a garage for 40+ years.
I also had some .380 Auto ammo given to me by my father, because he decided not to shoot reloads in his .380s any more. The load was safe and sane, so I tried it in my .380s, only to find that none of the primers were seated properly. Depending upon the pistol in question, it took 3 to 10(!) strikes to set the primers off.
....I don't think I've ever had a failure to fire with 7.62x54R, but I have had issues with factory ammo piercing primers. Surplus ammo and reloads have never done it, but several low grade brands of factory ammo have had 50% to 90% of the primers pierce. "Hot Shots" brand was the worst, with 18 of 20 primers piercing in my M38 or my brother's M44.
I need a new signature. This one sucks.