Solving Ar 15 Feeding Problems 762x39

October 06, 2022 Post a Comment

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has any one had any trouble with the ar upper not working well with the 7.62 x 39 upper if you did what kind of ammo did you use to correct the problem thanks Bruce
What do you mean "trouble with the ar upper not working well with the 7.62 x 39 upper"? Your statement is redundant and confusing.
Most troubles that are different with the 7.62x39 can be solved with the following items:

1. Enhanced 7.62x39 firing pin which allows for more pin protrusion for the harder russian primers, this is more than likely your problem.
2. Good mags, I like C-Products mags. Make sure that the front of the mag (the thin side) has enough clearance so the rim of the cartridge doesn't catch the front metal of the mag.
3. Feed ramps that are wider than normal to allow for the taper of the cartridge, this was a problem 10 years ago, but most barrel manufacturers have since solved this issue.
4. Some people have trouble with lighter weight hammer springs, I've had milspec trigger and now have LaRue trigger in mine and both ignite the primers just fine.
xds45 Member

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I held off getting that caliber upper because of all the stories I read of people having feed issues. I saw a deal for a complete upper for 200 bucks so I jumped on it, figured I would work thru the problems I encountered. I read up on the fixes people came up with, bought C products mags and an enhanced firing pin installed in a Bear Creek upper and 120 rounds with zero malfunctions.
Mine works perfectly. What issue are you having?
seems like any problem they have is with the feed ramp on the barrel ex the normal m4 ramp needs the middle of it ground off to make the ramp wider for the 311 bullet. other then that they are good to go. the bear creek arsenal are nice and are under 300 bucks.

boom boom and <*(((>< like this.
A lot of the 30rnd magazines will fit 30, but won't properly feed 30. My experience with these is if you load more than 27 in them the first three are likely to result in FTF.
I believe most of these were actually sold as 27rnd or something like that till recently.
I've got three x39 uppers and they all work great. The enhanced firing pin, .and the new model C Products Defense mags are almost mandatory. Light hammer springs are a big problem with Russian ammo. With brass case ammo they work fine.

boom boom and <*(((>< like this.
The only mags I have for mine are C products 10 rounders. For my uses I have no desire for anything bigger. I did not have any problems with the firing pin my BCA bolt carrier came with and steel case ammo but I did put in the enhanced firing pin after about 50 rounds just for good measure. Its cheap enough that its a no brainier to get. I have a standard power hammer spring in it.
I built mine about 6-7 months ago. It's been flawless. I estimate around 1100-1200 rounds down the pipe using Wolf, GT, Yugo and reloads.
Slick side upper, Aim Surplus BCG, H buffer, adjustable gas block, Faxon Gunner barrel.
I have C Product and ASC mags. I use 20 round mags because I hate 30s.
I recently installed a Larue trigger group and cheap 9x scope.
My AR Stoner 7.62x39 has been 100% reliable with any ammo I've tried and even my reloads. I'm using a standard "milspec" lower and just slapped the upper on it. I have a few 10 round ASC mags and they've been flawless. The 5 round Pro Mag I tried got thrown in the trash within 5 minutes (biggest pile of crap I've ever had that was firearm related)
Same for me with the AR Stoner upper. Added the following from Black Rifle Arms: enhanced firing pin, some C-Products mags and a Wolff Extra power hammer spring.
http://www.blackriflearms.com/AR-762x39-Enhanced-Firing-Pin_p_9.html 11 bucks

http://www.blackriflearms.com/C-Products-Defense-762x39-28rd-Magazine-Black-T-Finish-_p_419.html 20 bucks each

http://www.blackriflearms.com/-WOLFF-Extra-Power-Hammer-Spring_p_217.html 5 bucks

100% with Tula, Silver / Brown Bear, Red Army and all the brass American stuff I have used so far.

It's a fun, inexpensive and easily found caliber and certainly gives me an option to the 5.56 AR's. (It's no 6.5 Grendel for longer range stuff tho...)

Stay safe!
M1key Member

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Op, we need a little more info.
M
Other people report success, but I couldn't get anything but ten round mags to feed 100%. Not a big deal for me though. Not to mention I got bored with it and sold it cheap to a buddy.
I was just trying to get any outside option's about buying a upper in this caliber I am so sorry that I am incomplete and redundant but the original was like I stated it. If you are having trouble with yours what is it.
M1key Member

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My Colt carbine upper runs 100% and only gets brass cased ammo (factory or reloads) because many have reported bolt breakages with steel ammo. There is a "superbolt" out there that the manufacturer claims is guaranteed to run 10,000 round of steel ammunition. I have one and use it as a backup to the Colt bolt.
I use ASC 10 and 20 round mags.

Some other advice:
https://www.alloutdoor.com/2014/11/25/making-ar-15-7-62x39-work-reliably/

You can follow this guy's journey:

M
I disagree with the above article that the vast majority of people have issues, all gas ports are undersized and split feed ramps won't work. I've had 3 7.62x39 barrels. I've used an adjustable gas block all 3 of mine and was able to turn them down significantly so none were undergassed. They all also had split feed ramps which are enlarged slightly with a larger radius. 2 of them came that way and the last one I opened up before installing. All 3 of mine worked 100%. If you have feed problems it's probably the mags.

boom boom and <*(((>< like this.
I almost got one of these today, even had it in the cart and started to check out...
https://www.midwayusa.com/product/977284/ar-stoner-ar-15-carbine-kit-with-complete-upper-assembly-762x39mm-1-in-10-twist-16-barrel

Then I remembered how PO'ed I got last time they hosed me on a deal.

I should learn to let things go...
M1key Member

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Weell, I had a 20 inch that I had to drill out the port TWICE and still it would only cycle Golden Tiger. Made a few calls to the manufacturer about it never could get the "lead technician". He was always "not available right now" or "just stepped out"...yeah right. Never did get satisfaction. Sold it to a guy who cut the barrel off at the port and went SBR. I have heard of others who had gas problems--don't what length gas they had--but problems are out there.
M
My Yankee Hill Machine barrel has ran perfect from day one minus a a couple of feeding issues in the first 10 rounds. No drilling of the gas port and no adjustable gas block, and the feed ramps were already enlarged from the factory. But I don't buy cheap on barrels and bolts period, economy barrel and bolts never made sense to me.
Depends on what you mean by cheap. MAS is cheap for 7.62x39mm AR parts and they work very well. Built one that ran awesomely using stuff by them.
Glad it's worked for you.
Last Christmas I bought a carbine gassed 16" x39 upper from PSA for $149 shipped. Added a PSA BCG and charging handle I already had, and ran the snot out of it. It ejects to 3:00, and has been very reliable. Wouldn't hesitate to buy another.
My Bear Creek Arsenal upper has been just fine. The only modification I have done is changing the firing pin.
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boom boom Contributing Member

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Darn it, y'all talked me into starting a 7.62x39 upper build just to play around with it. Already had a spare bolt (sold as a Brownell's grendel bolt) and an upper laying around, now got a email flier on a 16 inch barrel for 49.99, and away we go.
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boom boom Contributing Member

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A few posters on AR15.com speculated that the gas pressure in the long 20 inch barrel dropped quicker than a .223 and thus a rifle length system is undergassed in the 7.62x39 and a carbine or even a mid length would perform better. Have no idea if they knew what they were talking about.