5.45x39 AR Uppers?


So recently I had a parts failure on a Midwest Industries AK handguard and now my dot can't hold a zero on my AK74 (99% sure this was an installation error on my part) so while I was a bit bored today I was kicking some ideas around in my head about overall cartridge length and I decided to see if 5.45x39 rounds would work in PMAGs. And at least initially it seems like they sorta do. That got me more curious and I did a little research, a few companies have made 5.45x39 parts for ARs in the past. I would love to hear from anyone with knowledge on the subject matter about how this idea actually goes into practice. If there isn't anybody who can speak authoritatively on the subject I'd be happy to experiment a bit and try putting together an upper.


I guess because ammo costs or something, these were a tiny bit of a thing like 15 years ago. Not common, but not rare, and not expensive.

Here's a contemporary article from an LFer on the topic, with broken photos but the text is there:

Many thousands of rounds, which comports with my basic memory: so did work just fine. Some tips on magazine compatibility are in there also.

Joe _K

First AR I bought was a S&W M&15R chambered in 5.45x39. It was a 2MOA 16” M4 pattern rifle. Used C Products 26 round magazines and it shot pretty well. I was using cheap Russian Mil Surprise corrosive ammo so the added steps of washing and then drying the rifle were really my only complaints. One time the thing went runaway full auto on me and S&W fixed it for free. Aside from that, it was a great, cheap rifle. I wish I hadn’t sold it as S&W discontinued that model some years back, but then again 5.45x39 doesn’t cost $0.11/per round any more either.