I cleaned the used rifle up real good, put 100 rds down range and it still jammed, mainly stove piped or over-ride, just really bad extraction. I took an old M-16 chamber brush on one section of rifle rod, chucked it in my variable speed drill & polished the chamber with some fine grade rubbing compound. The empty cases had been dragging in a rough chamber. Slowing them down enough to cause a jam. End of problem.
I would definitely start by completing the above (highly visible
) tasks. Many folks flat out do not EVER
clean their AKs. I used to be one of them. This applies mostly to the AK-47 rather than the 74, but MANY AKs can be shot through the life of the bolt/carrier group with out a cleaning.
Start with a typical cleaning and if it appears to have excessive fouling, keep going until you feel confident that EVERY moving part can do its job.
All the surplus 5.45x39 I've ever used is Bulgarian. Some of the guys I shoot with had problems with certain lots of the Russian surplus. Others have said their AK-74s didn't break in & run perfect till after around 300 rds?
Another thing, ALL my AKs love grease. I use a Q-tip & white lithium on all wear areas of the bolt & a light film inside the rails. Some guys use oil but I lube my AKs like they were a Garand or M-1A. This is just what I ran into, hope you get yours 100%. Ken
I've shot ammo from countries other than Bulgaria, but the majority is
from there and is AT LEAST mildly CORROSIVE!!!
, even if it says it isn't. Now I've never heard of, or experienced any AK having a "break in" period. Mine have, for the most part ran consistently without a hiccup for years, nearly decades.
Between shooting Mil-surp ammo and putting your rifle up for storage, use an ammonia based solvent VERY thoroughly.
There are commericially available options from Midway USA or you can use Windex in a water solution and give your gun a "bath". It sucks watching out for the furniture and stuff, so just get the solvent.
NO AK SHOULD RUN AS YOU DESCRIBED!
Something is really wrong and it's deeper than the type of ammo and/or magazine.