Here's what I know, and I don't reload, so I really don't have much in the way of testing this. I purchased Wolf 55gr. ammo, and when testing it at the range, it caused a bolt jam. I had to hit the charging handle on my AR(built using a Ballistic Advantage upper) with a rubber mallet to knock it loose. Then I had to use a set of tweezers to work the cartridge loose as it was stuck in the chamber(technically a set of computer chip pullers, the notches on the ends gave me just enough leverage to get the cartridge out). I tried this a few times with three different rounds, all had the same result. I recently ordered Red Army Standard 69gr ammo, it feeds perfectly. I provided quite a few pics to Ballistic Advantage, and they advised me about the ammo problem. I'm inclined to believe them. I've sent two emails now to Wolf(one via their contact us link on the website, another via their Return Authorization email that's on their website) and have not heard anything back from them as of yet.
Here's a few pics comparing the various ammo types I have for a sense of scale.
Picture 1:
Wolf 55gr 5.45, LC 149gr 7.62, Wolf 55gr 5.45, LC 55gr 5.56, Wolf 55gr. 5.45
Picture 2:
LC 149gr 7.62, RedArmy 69gr 5.45, Wolf 55gr 5.45, LC 55gr 5.56, RedArmy 69gr 5.45
I've only recently gotten in to shooting non-US calibers, and this is my first foray in to the 5.45x39 world... naturally I didn't pick the easiest way by building an AR to shoot in instead of just buying an AK :)