I'm at work and I can't post pictures from photobucket but right after Trump won the prez I put together an AR in 7.62x39.
https://www.midwayusa.com/product/104578/ar-stoner-ar-15-a3-upper-receiver-assembly-762x39mm-16-barrel
This is the AR Stoner upper. I paid $289 for it on sale. 3 Stoner mags, 2 30 and 1 10 rnd.
Anderson stripped lower, dpms lower parts kit. ATSbuffer magpul etc.
I've put 100 rounds of Herters brass and about 400 rounds of Russian steel, golden tiger, brown bear tula, etc. No fte or ftf's. it all 500 rounds.
I used an enhanced firing pin (read longer) and a stronger hammer spring which solves the biggest problem w/steel Russian ammo.
Just under $500