I'm only forming a theory at this point, but it seems that the reliability of surplus ammo depends on how long it has been sitting in storage. (Yeah, in hindsight it was an obvious realization.) I bought some Romanian from the 1970's that was great. Later this summer I bought some "Russian" without checking the headstamps or labels that turned out was mismarked, and was actually 1950's Bulgarian, and it was terrible. From here on out I'm asking both where and when it was made.
Scott