AR in x39?

it’s been discussed on forums for a long time now. to,accommodate the x39 into an AR the bolt face has to be enlarged. The lugs are poorly supported. My Wyndham weaponry factory x39 AR would shear bolt lugs constantly. Thankfully Windham CS was great and would replace the bolt for me every time, but it got annoying to the point that i replaced the barrel with a 16” BCM mid length which was a good move.

The magazine is the other issue. Tapered cases in a straight mag It’s simply not going to run as reliably as a 5.56/300 blockout. One can see just by loading them, the rounds do not fit snugly up against each other. There is a tendency for the top rounds to nosedive. i found ASC 10 round mags to be the most reliable, which seems to be the general consensus.

CMMG built the Mk47 (previously called the mutant) to address the above Issues. It runs a larger 308 / SR-25 sized bolt face but with an AR-15 length BCG. the bolts last forever. They also built the rifle to run on AK Mags which is The only way to run those rounds reliably. The error, in my opinion, was they kept an AR style charging handle which is annoying in the absence of a LSHO. They should have built it with a side charger on either side.

Setting aside the disadvantages of an AR in 7.62x39, they are still soft shooting, pleasant and definitely more accurate than an AK. as a fun/project gun they have a place. But as a purpose rifle no thanks. Personally if i wanted a fun and accurate rifle in 7.62x39 i would go with either a ruger American ranch, howa mini action or a CZ 527.

now I’m sure there are people out there who have never encountered a single bobble with their AR in 7.62x39 but i also don’t believe they’re shooting all that much. The 6.5 grendel actually suffers from similar issues as the 7.62x39 but not quite as severe.

This gives me pause. I built two and stocked up on cheep steel when I saw the writing on the wall regarding prices. Maybe I’ll buy a spare bolt as insurance. But I was hoping to be able to run a few thousand rounds through them to keep/increase proficiency on the platform
 
it’s been discussed on forums for a long time now. to,accommodate the x39 into an AR the bolt face has to be enlarged. The lugs are poorly supported. My Wyndham weaponry factory x39 AR would shear bolt lugs constantly. Thankfully Windham CS was great and would replace the bolt for me every time, but it got annoying to the point that i replaced the barrel with a 16” BCM mid length which was a good move.

The magazine is the other issue. Tapered cases in a straight mag It’s simply not going to run as reliably as a 5.56/300 blockout. One can see just by loading them, the rounds do not fit snugly up against each other. There is a tendency for the top rounds to nosedive. i found ASC 10 round mags to be the most reliable, which seems to be the general consensus.

CMMG built the Mk47 (previously called the mutant) to address the above Issues. It runs a larger 308 / SR-25 sized bolt face but with an AR-15 length BCG. the bolts last forever. They also built the rifle to run on AK Mags which is The only way to run those rounds reliably. The error, in my opinion, was they kept an AR style charging handle which is annoying in the absence of a LSHO. They should have built it with a side charger on either side.

Setting aside the disadvantages of an AR in 7.62x39, they are still soft shooting, pleasant and definitely more accurate than an AK. as a fun/project gun they have a place. But as a purpose rifle no thanks. Personally if i wanted a fun and accurate rifle in 7.62x39 i would go with either a ruger American ranch, howa mini action or a CZ 527.

now I’m sure there are people out there who have never encountered a single bobble with their AR in 7.62x39 but i also don’t believe they’re shooting all that much. The 6.5 grendel actually suffers from similar issues as the 7.62x39 but not quite as severe.
Well said 92G and I agree with your statements. An AR10 bolt has more meat and is the best option for x39’s. I also have a Cz527 which per manual loves the steel case best (That is an awesome rifle). I have some Belom brass to try out. I use ASC too. A little vid from NH. Don’t mind the hanging sling. My mlock came loose from the blast lol. Turn your volume waaaay up 😄

View: https://youtu.be/gIZmKXtSlDA
 
If you want something off the shelf in x39 that is not an AK, I had the Sig 556R, which is a piston driven AR-like rifle that takes AK mags. It worked great. They are hard to find around here though.
 
Just saw this somewhere here on NES today:

 
I took the plunge and splurged ( 🤡[laugh] ) on the Gen 2 Bear Creek Arsenal 10.5" x39 upper....Also bought some 10 round C Product steel mags.
It's got their new bolt and enhanced firing pin so I shouldn't have any light strikes. We'll see.

I have their 10.5" 5.56 upper and it has been flawless so far. These are just range toys and I only run steel case ammo through them.
 
lol well it was simply a matter of swapping in a stronger hammer spring and problem was instantly solved. Or I could run every round through twice and the primers would light after a second strike.
I think you said you have the BCA upper as well. If you reach out to them you can get their new enhanced firing pin to solve the light strike issue.
 
I have 3 that I've built so far and all 3 are having trouble digesting steel case Tula.
Brass not an issue.
I'm beginning to suspect it's that lot of Tula though because the case mouths look a little rough on some of them even though the rest of the case checks out fine.
Failure to chamber completely and stuck rounds that have to be mortared out.
 
I have 3 that I've built so far and all 3 are having trouble digesting steel case Tula.
Brass not an issue.
I'm beginning to suspect it's that lot of Tula though because the case mouths look a little rough on some of them even though the rest of the case checks out fine.
Failure to chamber completely and stuck rounds that have to be mortared out.
Ahh shit. I have a crapton of Tula I was planning to run...
These BCA x39 uppers?

Have you played around with buffer weights/springs? Or maybe might need a new extractor?
 
I will add that I’ve shot all Russian brands with no issues in mine and there have been maybe a few light primer strikes but imho that is a standard if you’re not running an AK.
 
Just saw this somewhere here on NES today:

Those are junk, the bolts crack &/or break
 
Who the fugg pays $1700 for am M+M?
I just got an email today from Palmetto (sorry Ma**h***s) with one of their own, well reviewed AKs for $699. Who pays Galil ACE money for an M+M?
 
I have 3 that I've built so far and all 3 are having trouble digesting steel case Tula.
Brass not an issue.
I'm beginning to suspect it's that lot of Tula though because the case mouths look a little rough on some of them even though the rest of the case checks out fine.
Failure to chamber completely and stuck rounds that have to be mortared out.
Good to know tula is still garbage. Had 2 squibs in a case like 10 yrs ago. Both in an SKS. Fortunately the round didn't go far enough to let next round chamber.

Wolf, golden riger, red army, barnaul, the Bears in 7.62x39 have all been great in my AR, sks, vz58. I wanted a common caliber.🤣 Really want a Cz-527 next.
 
I remember paying $350 for a Norinco SKS at Four Seasons back in 2012 or 2013. Looking back I definitely overpaid (at the time) but it was in nice shape. Didn’t know any better as a noob gun owner.
Ouch … sign of the times (OK Boomer …) but I recall paying $95 for mine there along with a plastic case & 100-rounds of Norinco copper-washed case ammo, for a then SWEET $100 out the door!

BTW, that ammo, albeit corrosive, is surprisingly accurate and amongst the best feed in my SKS or -39mm AR.

FYI, one option I highly recommend on any AR build in the -39mm platform is an adjustable gas block.
 
Ahh shit. I have a crapton of Tula I was planning to run...
These BCA x39 uppers?

Have you played around with buffer weights/springs? Or maybe might need a new extractor?
I have some other brands as well but haven't tried them yet. I bought a chamber hone to try to loosen up the chambers. It helped a little. Still sticking even when I just manually cycle rounds without firing.
 
Ahh shit. I have a crapton of Tula I was planning to run...
These BCA x39 uppers?

Have you played around with buffer weights/springs? Or maybe might need a new extractor?
No I haven't had the time to dick with those yet. Still doesn't explain why the rounds stick in the chamber.
Empty chamber bolt goes into and out of battery clickety clack lickety split.
Throw a mag in and it picks up a round and drives it home. Then you go to cycle the bolt and eject it. Sometimes it works. Sometimes it needs an extra tug. Sometimes you have to slam the stock on the floor while yanking the charging handle.
 
FWIW my -39mm barrel by ARD digests Tula w/ no problems & prints it pretty good, even lights off from a Gieselle SSA-E trigger.

It could be the JP Enterprises gas block, but so far … 13 or more brands later, and there isn’t 1-round/brand that it hasn’t failed to fire.
 
The first was built from a side charging upper I had around and a barrel I ordered from CFA. That one works well. Seemingly.
The second was a conventional upper with the the second barrel from the same supplier. ( both purchased at the same time)
That's where the trouble started.
So of course I needed third.
Pistol length.
Bought as a complete upper.
BCGs from the Ram.
Super duper firing pins and heavy hammer springs from another supplier.
 
FWIW my -39mm barrel by ARD digests Tula w/ no problems & prints it pretty good, even lights off from a Gieselle SSA-E trigger.

It could be the JP Enterprises gas block, but so far … 13 or more brands later, and there isn’t 1-round/brand that it hasn’t failed to fire.
Tending to think that ammo is the issue.
Pretty sure this lot was purchased over the last 8 months.
Should have much more time to work it out after my employer forces me to retire due to refusing to get the jab🤣
 
Good to know tula is still garbage. Had 2 squibs in a case like 10 yrs ago. Both in an SKS. Fortunately the round didn't go far enough to let next round chamber.

Wolf, golden riger, red army, barnaul, the Bears in 7.62x39 have all been great in my AR, sks, vz58. I wanted a common caliber.🤣 Really want a Cz-527 next.
CZ527???
E4896A34-C4BC-40A6-BCDF-DCD765323353.jpeg

Yeaaaaaah buddy 😎
 
Good to know tula is still garbage. Had 2 squibs in a case like 10 yrs ago. Both in an SKS. Fortunately the round didn't go far enough to let next round chamber.

Wolf, golden riger, red army, barnaul, the Bears in 7.62x39 have all been great in my AR, sks, vz58. I wanted a common caliber.🤣 Really want a Cz-527 next.

CZ527???

Yeaaaaaah buddy 😎

I own a Zastava M85 in 7.62x39 and one of my NH friends (who has a .30-cal Silencerco can in NFA jail) recently bought a threaded CZ 527 in .300. I'm looking forward to comparing the guns and cartridges.
 
No I haven't had the time to dick with those yet. Still doesn't explain why the rounds stick in the chamber.
Empty chamber bolt goes into and out of battery clickety clack lickety split.
Throw a mag in and it picks up a round and drives it home. Then you go to cycle the bolt and eject it. Sometimes it works. Sometimes it needs an extra tug. Sometimes you have to slam the stock on the floor while yanking the charging handle.

My first few shots in my x39 AR build didn’t even cycle the action at all. Super sticky case/chamber situation. I ended up buying a chamber brush, putting it in a drill, and giving her a few good spins with some flitz polishing compound for good measure. Cleaned it right up and have never had an issue since.
 
May need to go with polishing compound.
The hone and oil takes forever but I'll give it another go before more aggressive measures are taken.
 
I was so close to doing one of these.
But then i started readijg about it mire and more.

Pretty much unless you gett the cmmg monster(i think) its problem city.

One day, ill just get a galil ace
 
I was so close to doing one of these.
But then i started readijg about it mire and more.

Pretty much unless you gett the cmmg monster(i think) its problem city.

One day, ill just get a galil ace

If you want absolutely turnkey, no fiddling whatsoever, then yeah probably right.

My experience was mostly that getting a 10.5 with a carbine length gas system to run was, enlightening. Mags are what they are, pay for the good ones or learn how to make them work for you.

All in all I really like the x39 AR platform. especially in a shorter configuration. It’s like a poor mans 300blk. Seeing as I’m a resident of the land of hearing damage and no fun, the limited selection of suppression friendly ammo in x39 doesn’t hold me back
 
If you want absolutely turnkey, no fiddling whatsoever, then yeah probably right.

My experience was mostly that getting a 10.5 with a carbine length gas system to run was, enlightening. Mags are what they are, pay for the good ones or learn how to make them work for you.

All in all I really like the x39 AR platform. especially in a shorter configuration. It’s like a poor mans 300blk. Seeing as I’m a resident of the land of hearing damage and no fun, the limited selection of suppression friendly ammo in x39 doesn’t hold me back
ya I’ve already got a SBR lower so grabbing the 10.5" upper for $233 seemed like a no brainer. I love how light and handy my 10.5" 5.56 BCA upper is. I LOVE my Arsenal SAM7 AK but it’s not exactly light.

AR x39 mags and ammo are cheap and plentiful.
Fingers crossed it runs okay.
 
If you want absolutely turnkey, no fiddling whatsoever, then yeah probably right.

My experience was mostly that getting a 10.5 with a carbine length gas system to run was, enlightening. Mags are what they are, pay for the good ones or learn how to make them work for you.

All in all I really like the x39 AR platform. especially in a shorter configuration. It’s like a poor mans 300blk. Seeing as I’m a resident of the land of hearing damage and no fun, the limited selection of suppression friendly ammo in x39 doesn’t hold me back
So what's a "good one" as far as mags go?

Dinking around in a rare spare hour tonight I found out the following:

CProducts mag anti tilt follower tilted and jammed when loaded to 20 rounds on a 20 round mag.

Duramag mag loaded to 20 rounds fed flawlessly multiple times when loaded with 20 rounds but it's a 28 round mag.
Hey my thumb got tired.

The ammo was not the Tula I mentioned before. Tryed Red Star this time just because it was in the next can.
 
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