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View Full Version : A 7.62x39 for ARs


BoringGuy45
05-09-11, 22:03
One of the problems often stated about the 7.62x39 in the AR is the fact that the taper is too much for it to feed reliably. I was thinking, if the case was straightened for better feed, was loaded hotter than a standard 7.62x39, and used .308 bullets for better accuracy, it would be an excellent round. I'd imagine you could get a good 2550-2600 fps with 125gr rounds and with better downrange performance. Has this been tried before?
rsilvers
05-10-11, 07:29
It would still be a nogo due to the large case head.
LMTRocks
05-10-11, 11:03
OP---if you want to do a x39 build you may by all means get it running pretty easily imho. I have two x39 uppers and all it takes is extending the feedramps a little bit and polishing them using up to 2000 grit sandpaper. They're as smooth as glass now. Also what you can look at is a PWS Diablo. I've seen them run on full auto, in x39. There's no arguing about that. The problems that faced the x39 5 years ago are about gone. There is enough information that you can read through to get an upper running perfectly. Get parts from AR Performance when they come available and use a stock firing pin. I might go that route one day and sell the $20 pins I have but until then I see no reason to do so. You'll find how addictive this caliber is to shoot when you send a 123gr pill downrange at 2400fps for the same price as a 9mm.
JasonM
05-10-11, 11:22
If you want a 762x39 AR, go for it, they can be made to run OK for sure.

If you are talking about making a new cartridge, that's the purpose behind the 300 AAC BLACKOUT- AK ballistics out of an AR platform, standard bolt, feeds 30 rds in standard 5.56 mags, uses the common .308 bullet, has straighter case walls than the x39, etc. etc.
Todd.K
05-10-11, 11:26
OP---if you want to do a x39 build you may by all means get it running pretty easily imho.

What mags do you recommend now?
BoringGuy45
05-10-11, 14:41
If you want a 762x39 AR, go for it, they can be made to run OK for sure.

If you are talking about making a new cartridge, that's the purpose behind the 300 AAC BLACKOUT- AK ballistics out of an AR platform, standard bolt, feeds 30 rds in standard 5.56 mags, uses the common .308 bullet, has straighter case walls than the x39, etc. etc.

I'm talking about something roughly the same size of the AK case but with straight case walls. AK rounds, from what's been said here, typically are not loaded to their full potential. The .300 AAC, at its full load, just reaches the 7.62x39 in terms of MV and energy with similar weight bullets. Because the x39's case is bigger than the .223 case, it can potentially be loaded hotter.
rsilvers
05-10-11, 15:01
There is 30 Gremlin. It is a 6.5 Grendel opened to 30 cal. Bolts will break though when you push this cartridge. Keep it to reasonable pressures.
LMTRocks
05-11-11, 11:45
What mags do you recommend now?

http://www.palmettostatearmory.com/1519.php
http://www.palmettostatearmory.com/146.php
http://www.palmettostatearmory.com/567.php
http://www.jsesurplus.com/10roundar68mag.aspx

You can also call Classic Arms and Archery here (http://local.yahoo.com/info-28981323-classic-arms-archery-lexington) and get them for $20/ea if PSA is out of the 30rd magazines. I bought a bunch last year and they still have a box full of them.
Todd.K
05-11-11, 12:18
https://www.m4carbine.net/showthread.php?t=75956&highlight=c-products
hunt_ak
05-13-11, 00:12
Anyone have any info/experience on the YHM uppers in x39???