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Thread: AK-74 burn-down test (Russian)

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    AK-74 burn-down test (Russian)

    Not really a discussion, but more of an FYI/entertainment.

    Here is a video of a Russian AK-74 burn-down performed by a Kalashnikov factory. In a nutshell:
    - military AK-74M (5.45x39) year of manufacture 2014
    - ammo - military 7n6, ammo can seems to be marked year 1977
    - at around 480 rounds barrel was drooping, rate of fire varies widely, significant fireballs from the muzzle, bolt carrier sticking in the action.
    - at around 580 rounds barrel fails and has a live round stuck in the chamber (probably due to heat melting a cartridge lacquer)
    - after the test the receiver and bolt look fine, everything else including the barrel, carrier (bent piston), and muzzle device are unusable.

    Interesting points:
    - barrel burst around a front handguard mounting point, not at the gas block
    - didn't notice any cook offs, although I was expecting to see some after 200-250 rounds
    - video was not filmed from the same vantage point so it's difficult to judge when the barrel started drooping, but by 450-480 rounds it was noticeable

    I'd like to see them do a burn-down of PKM. I suspect it will probably do 800-1100 rounds until a catastrophic failure.


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    Didn't the standard M4 get through that many rounds without barrel failure?

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    It kind of begs the question, at what barrel temperature should you stop shooting a rifle for fear of excessively wearing the barrel?

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    AK pencil barrel is not well suited for a high volume of fire. I wish an industry professional would chime in on this topic, but my suspicion is about 150-250 rounds depending on the barrel condition is the max most barrels can take without stripping rifling. I agree that would be a more interesting and practical test. As a reference point - If I recall correctly a MG-42 required a hot barrel swap after 250 rounds of continuous burst.

    Reading a source a few years back mentioned that AK barrels use a fairly low grade steel - something like 4130. Though, I'm not 100% certain a source was accurate. Another person mentioned that they are able to bring steel to have better properties using a special treatment process which took to develop close to 10 years in 1950's. Then of course the CHF process takes place which further improves steel characteristics.

    Not too impressive - I agree. But at least the test appears to be genuine without typical manufacturer inflated claims like "it can go on to shoot 1000 rounds without any wear" or something like that.

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    He says..... The internet is full of people who torture their firearms by shooting without stopping. This is not realistic for a firearm. Even the Kalashnikov is only expected to withstand 180 rounds of continuous fire. We decided to do our own test. For this we grabbed the first available AK, made in 2014. We have 27 magazines of 7n6. (Lists off all the safety stuff he's putting on).

    At the 240 round mark he says it feels like the rate of fire is increasing a little bit.

    At the 390 round mark. He says it feels like the rate of fire is inconsistent. Increasing/decreasing. The rifle is extremely hot.

    At 480. I can hear the plastic hissing and feel that the bolt is sticking

    At 540. It's becoming a little bit scary

    At 570. The bolt is sticking. Forced to chamber by mortaring

    Barrel burst around the handguard retainer. The plastic, while smoking and very hot it's still hard. Can't squeeze it or deform it.

    570 rounds without stopping of 5.45. we'll let it cool and take it apart to look.

    Bolt, carrier, piston, recoil spring, top cover don't appear to have any deformation.

    There's a case stuck on the chamberthat we'll have to take out later. The rim has been ripped off by the extractor.

    The gas tube has melted/welded on we can't take it apart any further

    (Standard don't try this at home)

    If you'd like to see us test any other weapon please leave a comment below

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    Quote Originally Posted by Bret View Post
    It kind of begs the question, at what barrel temperature should you stop shooting a rifle for fear of excessively wearing the barrel?
    I don't think these tests really answer anything. It's a rifle not a GPMG. Short controlled bursts and even then you have to know when is when. What I've learned is gas tubes melt and AKs catch on fire. Also a sample of one is meaningless. It's not a standard threshold because so many factors are involved.

    If you are mag dumping more than three magazines you are probably dead anyway. Blaze away and make sure you have a handgun to check yourself out when the time comes. Everything else is LARPing worries.
    It's hard to be a ACLU hating, philosophically Libertarian, socially liberal, fiscally conservative, scientifically grounded, agnostic, porn admiring gun owner who believes in self determination.

    Chuck, we miss ya man.

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    Quote Originally Posted by alx01 View Post
    AK pencil barrel is not well suited for a high volume of fire. I wish an industry professional would chime in on this topic, but my suspicion is about 150-250 rounds depending on the barrel condition is the max most barrels can take without stripping rifling. I agree that would be a more interesting and practical test. As a reference point - If I recall correctly a MG-42 required a hot barrel swap after 250 rounds of continuous burst.

    Reading a source a few years back mentioned that AK barrels use a fairly low grade steel - something like 4130. Though, I'm not 100% certain a source was accurate. Another person mentioned that they are able to bring steel to have better properties using a special treatment process which took to develop close to 10 years in 1950's. Then of course the CHF process takes place which further improves steel characteristics.

    Not too impressive - I agree. But at least the test appears to be genuine without typical manufacturer inflated claims like "it can go on to shoot 1000 rounds without any wear" or something like that.

    One of the reasons why the AK selector lever has "semi auto" all the way at the bottom is because a panicked soldier will push the selector to the bottom. This forces a soldier to make a conscience decision to then return the selector upward to the auto position when needed. They also knew that the weapons weren't going to handle more than a few mags back to back on auto without over heating. So running them on semi auto is their preferred method especially once going to thinner barrels in AKM's and 74's from their heavier barreled 47's. Their barrels are decent but not really any harder than our 4140 steel barrels despite them using the Steyr hammer forging technique. Rounding the numbers out, their barrels range on the low end from 22 rc for Romanian barrels, to 27 RC for Bulgarian, and even as high as 30 RC for Polish barrels. While a typical US made 4140 CMV barrels might range from 26 to 28 rc. Final thoughts, though I prefer the lighter weight/more accurate 5.45 or 5.56 AK rifles, if I was going to recommend buying an AK today, I'd just suggest sticking to 7.62x39 since that round runs at a lower pressure thereby extending barrel life for the rifle itself.

    RC barrel hardness testing for AK import and domestically made barrels.
    https://modernrifleman.net/2015/10/1...rily-the-best/

    Notes on barrel longevity running copper bullets with brass casings vs copper washed steel bullets with steel casings.
    https://www.luckygunner.com/labs/bra...el-cased-ammo/
    Last edited by RetroRevolver77; 10-01-19 at 06:38.

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    Quote Originally Posted by RetroRevolver77 View Post
    One of the reasons why the AK selector lever has "semi auto" all the way at the bottom is because a panicked soldier will push the selector to the bottom. This forces a soldier to make a conscience decision to then return the selector upward to the auto position when needed. They also knew that the weapons weren't going to handle more than a few mags back to back on auto without over heating. So running them on semi auto is their preferred method especially once going to thinner barrels in AKM's and 74's from their heavier barreled 47's. Their barrels are decent but not really any harder than our 4140 steel barrels despite them using the Steyr hammer forging technique. Rounding the numbers out, their barrels range on the low end from 22 rc for Romanian barrels, to 27 RC for Bulgarian, and even as high as 30 RC for Polish barrels. While a typical US made 4140 CMV barrels might range from 26 to 28 rc. Final thoughts, though I prefer the lighter weight/more accurate 5.45 or 5.56 AK rifles, if I was going to recommend buying an AK today, I'd just suggest sticking to 7.62x39 since that round runs at a lower pressure thereby extending barrel life for the rifle itself.

    RC barrel hardness testing for AK import and domestically made barrels.
    https://modernrifleman.net/2015/10/1...rily-the-best/

    Notes on barrel longevity running copper bullets with brass casings vs copper washed steel bullets with steel casings.
    https://www.luckygunner.com/labs/bra...el-cased-ammo/
    So that may be the claim today, however in Russia everything is expendable. People, small arms, ammo. Post WWII the Russians KNEW they didn't have an army of Daniel Boones, full auto is the first position because the Russians understood what worked in WWII was heavy fire on the enemy. That's why there were so many PPSh41s out there during the invasion of Germany. So when the first AK-47s were developed, it was with a volume of fire doctrine in mind. That is also why they made it reliable at some cost to accuracy potential.

    Obviously with evolutions to the 100 series that mindset changed.
    It's hard to be a ACLU hating, philosophically Libertarian, socially liberal, fiscally conservative, scientifically grounded, agnostic, porn admiring gun owner who believes in self determination.

    Chuck, we miss ya man.

    كافر

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    interesting test..

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    Quote Originally Posted by SteyrAUG View Post
    So that may be the claim today, however in Russia everything is expendable. People, small arms, ammo. Post WWII the Russians KNEW they didn't have an army of Daniel Boones, full auto is the first position because the Russians understood what worked in WWII was heavy fire on the enemy. That's why there were so many PPSh41s out there during the invasion of Germany. So when the first AK-47s were developed, it was with a volume of fire doctrine in mind. That is also why they made it reliable at some cost to accuracy potential.

    Obviously with evolutions to the 100 series that mindset changed.
    I've heard it from both sides. Generally the people looking at the layout- assumed that they would run them on auto since auto is the first position. However those in the AK business would state the AK was purposely designed so that panicked soldiers would push that selector down till it stops- which is on semi auto to help the soldiers focus. Personally I think it's an accidental attribute just based on the limitations of the mechanical function of the selector.

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