Assistance requested with 7.62x39 upper build...

[TED]

I would like to build a light weight 7.62x39 AR.

The foundation will therefore be a KP15 receiver which I already have completed.

I have secured a useful number of recommended mags.

I have an upper I can use.

I am looking specifically for a 16" mid-length gas barrel with standard front sight gas block with bayonet lug.

I have not been able to find a mid-length gas 7.62x39 barrel. I might have overlooked it, I do wear thick ass glasses for a reason.

The only thing I'm missing is a complete bolt and carrier assembly and the aforementioned barrel!

I am having a difficult time locating some that are of decent price and quality.

I looked at model 1 sales found their site uninspiring.

I looked at bear creek arsenal and was similarly concerned.

PSA is chronically out of everything.

Thoughts, ideas, suggestions?

TED

[Dutch110]

I used a 16" DEZ Arms barrel on my build with great results (see my thread later on down the page here.)

https://www.m4carbine.net/showthread...e-Aim-DEZ-Arms

They offer both a carbine and mid length option. They show out of stock on their web site right now but try Optics Planet. You would have to mount your own FSB. Also, I used a Rubber City Armory BCG and it's slicker than goose poop. Almost 1000 rounds of steel case later and no failures to feed, eject or any light primer strikes (also due to using a trigger with full power hammer springs.) Not saying this is the ultimate, just what worked and is working for me.

The one drawback is going to be this is definitely NOT a lightweight barrel. If you want lighter I think you're going to have to go shorter and consider a pistol length build

[Pressingonward]

I have not seen any lightweight 7.62x39 barrels on the market, much less a midlength gas 16", though it's been a while since I've searched.

You can get an 18" midlength barrel from Dez Arms (what I have in mine). If you call and ask nice maybe they'll do a custom 16" middy for you? KAK also offers an 18" midlength.

If you want to wait a year and pay for it, this place offers custom barrels in 7.62x39: https://columbiariverarms.com/produc...-configurable/

There are several options in 16" carbine - Dez and Green Mountain are the two I had noted down.

[Dutch110]

I have not seen any lightweight 7.62x39 barrels on the market, much less a midlength gas 16", though it's been a while since I've searched.

You can get an 18" midlength barrel from Dez Arms (what I have in mine). If you call and ask nice maybe they'll do a custom 16" middy for you? KAK also offers an 18" midlength.

If you want to wait a year and pay for it, this place offers custom barrels in 7.62x39: https://columbiariverarms.com/produc...-configurable/

There are several options in 16" carbine - Dez and Green Mountain are the two I had noted down.

Right on cue I just got an email promo from KAK advertising their .39 barrels and BCGs but when I went to their page almost all of their barrels are out of stock

https://www.kakindustry.com/ar-15-pa...arrels/7-62x39

I should also have noted my 16" DEZ is carbine length.

[TED]

I'm very happy to hear that there are indeed 16" mid-gas 7.62x39 barrels!

Thanks.

TED

[rpoL98]

you do know that the pressure curve for 7.62x39 is lower than 5.56, something to do with powder burn, etc. So the desirable characteristics of the 5.56 mid-gas 16" don't exactly transfer to the 16" 7.62x39. which is why 7.62x39 carbine gas is so prevalent for 16" AR-15 implementation.

for 16" 5.56, mid-gas is the sweet spot. doesn't exactly translate to 7.62x39, probably has a relatively large gas port to make it function reliably. Tula steel-case seems to crop up as a weaker ammo in threads.

just my observation, MHO.

ETA: find your barrel, buy the .750" FSB, send it out to Adco or John Thomas for pinning (include the barrel nut, handguard cap). That way you end up with the barrel of your choice.

[TED]

you do know that the pressure curve for 7.62x39 is lower than 5.56, something to do with powder burn, etc. So the desirable characteristics of the 5.56 mid-gas 16" don't exactly transfer to the 16" 7.62x39. which is why 7.62x39 carbine gas is so prevalent for 16" AR-15 implementation.

for 16" 5.56, mid-gas is the sweet spot. doesn't exactly translate to 7.62x39, probably has a relatively large gas port to make it function reliably. Tula steel-case seems to crop up as a weaker ammo in threads.

Yep, I know.

I want the mid-gas for an entirely ridiculous and silly reason, to fit a bayonet on a 16" barrel.

Yep, really.

Don't worry, this is only a toy. I have other guns for defensive purposes.

TED

[Dutch110]

I didn't even think about gas port size. I know the one on my carbine length 16 inch is yuuuuge. Cant imagine how big it would need to be on a middy to work correctly.

[Bret]

I looked at model 1 sales found their site uninspiring.

Though I have not built it yet, I purchased a 5.45x39 barrel from Model 1 Sales. The quality appears great.

I looked at bear creek arsenal and was similarly concerned.

I purchased a Bear Creek Arsenal 7.62x39 upper half to go with a 7.62x39 marked Tactical Machining lower receiver that I purchased. Not only does it run 100% with the Tactical Machining lower half that I built, it runs 100% on full auto using my M16 lower half.

[Pressingonward]

I didn't even think about gas port size. I know the one on my carbine length 16 inch is yuuuuge. Cant imagine how big it would need to be on a middy to work correctly.

My 18" Dez Arms midlength has a 0.125" gas port, and is overgassed even with Tula and Red Army Standard, which I've heard are some of the weaker x39 rounds. Just put an adjustable gas block on it but haven't gotten it dialed in yet.