AK problems--Some developments

[John in WI]

I heard back from the person who sold the Polish AK parts set I bought. It turns out he didn't make the barrel, but it was made by a company called ESS.

It seems in ESS barrels the problems I'm reading about are that the rifling doesn't make one complete revolution over the length of the barrel, and they blame that for the key-holing problems that many are complaining about.

I contacted ESS but haven't heard back yet.

Is there anything you can do in terms of bullets to compensate for a not-tight-enough twist? I really am hoping to avoid pulling the barrel and installing a new one. It's a 7.62x39.

Thanks for any advice--I hope the answer isn't to get a new barrel!

[Ben]

Have you attempted to measure the twist in the barrel ?

[RU shooter]

And the barrel company does this on purpose? So it's like a 1:18 or 20 twist ?

[John in WI]

I have no idea if it's on purpose or not. It must be a 1:18 or 1:20 because I have a 16" barrel and it didn't make a full revolution when I pushed a patch down it. If I had to guess I would say 1:20.

[John in WI]

I had no idea that the twist rate was so tight in them. From what I understand it was either intentional or a "lucky" accident (if you fought in a commie country) but the bullets would fly straight, but tumble and yaw violently on impact. The 5.45 was supposed to be even worse (the so called "poison bullets").

I will have to look into feeding issues with blunt boolits. I haven't read anything about it because commercial/bulk ammo is so cheap very few people bother to reload for the AK. Neither would I--if I could find ammo that would hit the side of a barn at 50 yards.

[Lonegun1894]

The other option is to increase the velocity, but that is a fairly small case to be pushing too hard and you may run out of safety margin before you get anything moving fast enough, so be careful. I hope you can make this barrel work though.

[JAGGUY]

Lot's of discussions re this problem.
Here is one with some interesting thoughts...
http://www.calguns.net/calgunforum/showthread.php?t=502224&highlight=ess

[John in WI]

Thanks for those tips. I'll definitely read through the link and see. I only learned recently that the ESS barrels cause all kinds of problems, and was bummed out to learn that I'm cursed with one. It's not impossible to change barrels--but it certainly isn't an afternoon project either.

[lmcollins]

You should be able to look down the muzzle with a light in the breech and estimate the twist. If it is as slow as you indicated, you should be able to "see" it.
Look at something whose twist you know, and compare what you see.

I.e. a US Springfield is 1 in 10. My Remington 700 22-250 is 1-14. Understand what I'm saying? A strong light, and a half decent eyeball should tell you about what you have. A patch or a brush might not necessarily follow the rifling well.

Have you tried to slug the bore yet as I suggested?

[John in WI]

I haven't tried to slug the bore, but my eye and the cleaning rod test are showing me that there is less than one revolution over the length of the barrel. It is DEFINITELY not 1:10 as I learned is the standard twist for a 7.62x39.

On some of the AK forums, it seems that the solution is to get a new barrel. Either a surpulus Combloc, or a US made one from a known company. I heard the ones from Green Mountain are as good as US made barrels get. I may look in to that.

[Multigunner]

Some 7.62X51 NATO barrels use a 1:14" twist, though with a sixteen inch barrel and subtracting length of the chamber that should work out to aprox one turn from chamber mouth to muzzle.

I have heard of bore problems with some aftermarket barrels, but never found out the exact cause, bore diameter having been the prime suspect when these are discussed. Such a radical departure from standard rifling twist specifications is not something I'd have guessed.

The twist rate sounds more suited to one of the low velocity target cartridges like the 8.46X46 or .32-40.
I wonder if theres a 7.62 equivalent of these cartridges in Poland or some other former Combloc country.

The 7.65/.32 ACP pistol barrels usually use a 1:14 to 1:16 twist. Perhaps barrel blanks rifled for the pistol cartridge were used to make these barrels.

[Artful]

I haven't tried to slug the bore, but my eye and the cleaning rod test are showing me that there is less than one revolution over the length of the barrel. It is DEFINITELY not 1:10 as I learned is the standard twist for a 7.62x39.

On some of the AK forums, it seems that the solution is to get a new barrel. Either a surpulus Combloc, or a US made one from a known company. I heard the ones from Green Mountain are as good as US made barrels get. I may look in to that.

Yep, to shoot standard 7.62x39 ammo you'll need the correct twist barrel.
Did you contact the person you bought it from to see if they will make it right?

[x101airborne]

I had this same problem. ESS Solution is run by a German fellow named Andreas Schulz. He is the owner. I got a 7.62x39 barrel for my first AR project from him before he got the Remington barrel contract. He is now making the barrels for the Remington AR's. Anywho, I had the same problem, keyholing at 25 yards no matter what ammo or handload I tried. I contacted him and he immediately sent me a new barrel that was checked before sending it out. I still have the old barrel, but dont know what I will ever do with it. He is a very kind person and very receptive if you contact him with a problem. It may be easier to e-mail him and ask him to call you. Yes, he is that busy.