I saw a YouTube vid where a guy used these. Worked pretty well.
https://smile.amazon.com/eBoot-Black-TR-412-Rubber-Snap/dp/B01MYWZXYT/ref=sr_1_5?ie=UTF8&qid=1522463809&sr=8-5&keywords=valve+stem&dpID=51fz%252BaSy1hL&preST=_SY300_QL70_&dpSrc=srch
I built a 7.62X39 AR last year. Rounds wouldn't chamber or if they did, wouldn't eject properly. Somebody at the MFG put a .223 extractor in the bolt. Store sent a new extractor, now it cycles perfectly.
https://www.amazon.com/dp/B0047T4J20/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=2W5VLRIMOMVQP&coliid=IE9OS5HA55TO1&psc=1
These are good all around bags.
Dividers inside to separate ammo, mags, ears, tools etc.
2 zippered side compartments with padded pistol rugs.
I have 2, been using...
I've been using this for 4 years, Still holding up.
https://www.amazon.com/GunMate-Range-Removable-Hook-Dividers/dp/B0047T4J20/ref=sr_1_1?ie=UTF8&qid=1469158071&sr=8-1&keywords=gunmate+range+bag
The mil spec, if made properly made, has exaggerated threads on the elevation drum.
The cheap ones have standard threads.
I doubt if the elevation marks could be correct with such a small amount of movement.