Hey guys, I recently acquired a Russian IJ-70 Mak with the rear adjustable sight, original owner's manual says it was made in 1994. My Dad has had one just like it for 15+ years and it has never jammed, regardless of ammo used. I took mine out for the first time over the weekend and it was flawless through 100 rounds of FMJ, but wouldn't feed Hornady Critical Defense or the FTX. Does anyone have any recommendations of what I should try next? or what may be the problem? I'm leaning toward the mags being the issue but I have 4 of them and they all had FTF issues. Any help is greatly appreciated.