AK barrel length?

[jcabin]

AR barrel length is a highly debated topic. Several key points seem to be, "carbine length vs full size", "ammo to go with which length and twist", and "reliability".

Would anyone care to explain how these topics translate into the world of AK's? It seems AK barrels only come in two lengths, 16 inch and the RPK length which is what, 24 inches??

What are the advantages and disadvantages to these barrel lengths in an AK, and which ammo works best for what? I don't even know if you can select different twist rates on the most available AK barrels. Stock I think its 1:9.

I'm not looking to dump a ton of money into an AK, buying a custom, expensive barrel, to make it shoot at 500 yards with a more appropriate twist rate and the proper grain ammo. I was just wonder about the above question.

[mojo]

Honestly I never paid much attention to twist rate but on AK rifles (not krinks or anything like that) you basically have the two lengths that you listed.

Standard AK and RPK.

Differences:

RPK is thicker and longer.

No one really shoots AKs for their accuracy at 500 yards so it's not really as big of an issue as it is with ARs, and your right you don't specify your twist rate. They are what they are. The only ones that I can think of that are different are the krink type. I know that the 5.45 are different as there was recently a discussion about it.

The more accurate ammo has generally been the yugo and chinese surplus but I don't shoot those so I can't really comment.

Most AK owners don't worry about bullet weight vs twist rate vs barrel length. They just buy what is cheap and shoot the crap out of it. As far as barrel length on the initial purchase. 99% of owners can be lumped into 2 categories. Owners can have guns that fit into either group.

1. Buy what ever is there and cheap. (Shooters)
2. Buy it to match the original. (Collectors)

edit: AK-47 barrels are thicker than AKM barrels

[Willie D]

7.62x39 doesn't get a performance boost from a longer barrel the way 5.56 does. You lose maybe 100fps going from 20" to 16" so the bullet doesn't interact with the target differently coming out of either rifle. The longer barrel will have a marginal improvement at longer ranges.

The shorter barrel should actually be more accurate because it will be stiffer, less harmonics, etc. but the longer sight radius on the 20" may help you shoot better using iron sights.



RPKs are designed to get a little more distance out of the round but most importantly, they are heavier built to withstand the rigors of continued full-auto supressing fire. IMO, a semi auto RPK is just a heavier gun - although the RPK built Vepr rifles have a good reputation. The heavier barrel will probably keep groups together a bit longer than the pencil barrels on most AKMs but you'll pay for it in weight.

[jcabin]

7.62x39 doesn't get a performance boost from a longer barrel the way 5.56 does. You lose maybe 100fps going from 20" to 16" so the bullet doesn't interact with the target differently coming out of either rifle. The longer barrel will have a marginal improvement at longer ranges.

The shorter barrel should actually be more accurate because it will be stiffer, less harmonics, etc. but the longer sight radius on the 20" may help you shoot better using iron sights.

The arguement I heard was that the AK barrels are literally mosin barrels, made with mosin equipment at old mosin factories. Atleast they were during original production, but nothing has really changed since then.

That being said, the twist rate was never adjusted when stepping down from a much heavier bullet to a lighter bullet, and this would have affected the accuracy if it was done. Leading to a greater accuracy with the AK/7.62x39.

I don't know how true this is, but it's one arguement for the limited accuracy of the AK. I can't disagree with it. There's no reason why the design was built so short sighted other than that big mess up.

[mojo]

I would think that they would be closer to SKS barrels than Mosins but that's my opinion.

[Willie D]

The arguement I heard was that the AK barrels are literally mosin barrels, made with mosin equipment at old mosin factories. Atleast they were during original production, but nothing has really changed since then.

That being said, the twist rate was never adjusted when stepping down from a much heavier bullet to a lighter bullet, and this would have affected the accuracy if it was done. Leading to a greater accuracy with the AK/7.62x39.

I don't know how true this is, but it's one arguement for the limited accuracy of the AK. I can't disagree with it. There's no reason why the design was built so short sighted other than that big mess up.

That could be a factor in AK accuracy (or lack of) although wouldn't that mean the AK has too much twist for lighter bullet? Rifling twist is not really a subject I can pretend to know much about.



As I see it the things that hurt 7.62x39 AK accuracy the most are:

The Round - heavy and underpowered, trajectory like a rainbow

The Ammo - the stuff most people use is woefully inconsistant, spend a little more on ammo and you'll likely see some improvement

The Barrel - Is thinner than most .22 rimfires and shoots a bullet 4x as heavy. It WILL heat up, it WILL move.

The People Who Build AKs - The Israelis, Finnish, and South Africans made/make a better performing gun with the same design.

I'm not sure whether they just cared more about their finished product than Combloc workers or if they made a conscious decision to forego a tighter shooting AK in favor of more reliability, but as long as the bolt, trunnion, and chamber interface looks like a High School metal shop project, your potential for repeatable accuracy is going to be limited.

[scoutjoe]

The shorter barrel should actually be more accurate because it will be stiffer, less harmonics, etc. but the longer sight radius on the 20" may help you shoot better using iron sights.

This is the only argument that I've found to hold water. That Saigas in .308 (I know I know I'm jumping calibers) preform better with the shorter barrel with optics as opposed to the longer barrel.

If you go to irons then guys with long barrel (20" 7.62x39, 22" .308) come in ahead because the longer sight radius helps.

[knight0334]

Bullet lengths(weights) and operating velocities are pretty much within a narrow range with AK47's using 7.62x39mm ammo. ...so there is no real need to have a varying choice in twist rates.

The velocity difference between 16" and 24" might be 120-200fps. If that.. Which the twist rate is likely designed for the velocities of the shorter barrel. The additional velocity of the longer barrel wouldn't over-stabilize a bullet.

There are also 20" AK's too. Which will offer a happy medium between the 16" AK and the 24" RPK.

[jcabin]

Bullet lengths(weights) and operating velocities are pretty much within a narrow range with AK47's using 7.62x39mm ammo. ...so there is no real need to have a varying choice in twist rates.

The velocity difference between 16" and 24" might be 120-200fps. If that.. Which the twist rate is likely designed for the velocities of the shorter barrel. The additional velocity of the longer barrel wouldn't over-stabilize a bullet.

There are also 20" AK's too. Which will offer a happy medium between the 16" AK and the 24" RPK.

But if they never intentionally designed a barrel and twist rate specifically for the round, and just used the same format they used to make mosin barrels, then what would that do to your theory?

[ByAnyMeans]

I have found my AK's like 124 gr ammo the best and which manufacture really plays no part. They like 154 second and 115 least.

As stated before, how big a difference is not much. It's probably the difference between and 1 to an 1 1/2 group size. When we are talking three in. group then a four inch group is still good enough to get the job done for it's role without needing to worry that that is what lost you the medal for accuracy.