IV8888 Shoots A Vepr AK To Failure

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Gun blogger superstar Eric of the Iraqveteran8888 YouTube channel is happy to once again get behind a rifle going cyclic until failure. This time, Eric’s victim is a Vepr 7.62×39 AK rifle made by Molot and modified by Copper Custom. Those who watch these videos should know that burnout tests like this are not particularly safe; parts are liable to fail, rounds cooking off are a virtual guarantee, and they are – natrually – a fire hazard, as well. Having said that, Eric will do it so you don’t have to, so enjoy the video below:

The end result of shooting the Vepr was a weapon that locked up – the action unable to be worked by hand – after the end of 895 rounds of 7.62x39mm ammunition down the spout in one session. Eric previously tested a WASR-10 AK, which only was able to fire 265 rounds before the barrel drooped too far for the piston to align with the gas block, preventing the weapon from going into battery.

At the end of the Vepr test, Eric, undaunted by the gun’s failure, did a little Eastern Front armorer work on the rifle (banging the rifle against the shooting table), allowing the bolt to come back with less effort. He charged the rifle, and fired another 75 round drum through the rifle, which appeared to finally solve the problem and get the rifle back in action.

There’s a little post-hoc analysis we can do after the fact. Eric’s previous test of an AR-15 resulted in a barrel failure at 830 rounds, the rifle’s Faxon M4-profile barrel bursting just behind the gas block. One thing Eric does not mention is that these burnout tests are much more a torture of the barrel than they are of the rifle’s operating group. Certainly, as seen in the WASR test, the barrel can droop far enough that the gas block does not accept the piston head anymore, or in the case of some AR-15 tests, the gas tube can burst due to heat, but beyond that it is the barrel that takes almost all of the punishment in tests like these. So why did the Vepr perform better than either the AR-15 or WASR? Simply, because its barrel was a much heavier profile than the barrels of either of those rifles, and, vs. the AR-15, it was shooting a round (7.62×39) which generates less waste energy in the form of heat. Some basic statistics (collated by myself) about the barrels and ammunition of the three rifles is given below:

Vepr barrel:

Cold hammer forged, chrome-lined, 0.790″ diameter heavy profile, .311″ internal diameter

Barrel wall thickness: .2395″

Failure point: 895 rounds

 

AR-15 barrel:

Drilled, button-rifled, nitride 0.750″ (gas block)/0.640″ (under handguards*) diameter M4 profile, .224″ internal diameter

Barrel wall thickness: .2080″ (under handguards*)

Failure point: 830 rounds, *note that failure occurred under the handguards

 

WASR-10 barrel:

Cold hammer forged, chrome-lined, .592″ diameter AKM profile, .311 internal diameter

Barrel wall thickness: .1405″

Failure point: 265 rounds

Below the respective thermal efficiencies of 5.56x45mm and 7.62x39mm have been calculated. The thermal efficiency was derived from Powley computer calculations. Wasted heat is the remainder of the energy created by the cartridge that is left in the barrel; this is the primary cause of barrel heating during firing (heating due to friction is a small fraction of total heat created):

5.56×45:

Thermal efficiency: 27.1%

Wasted heat: 4339 J
7.62×39:

Thermal efficiency: 34.4%

Wasted heat: 3877 J

Just taking these numbers at face value, we should expect a 5.56mm barrel to fail at 0.89 times the rounds that an otherwise identical 7.62x39mm barrel fails at. Given that we saw a catastrophic failure of the AR-15 at 0.93 times the round count at which the 7.62x39mm Vepr’s barrel began to fail, this prediction actually aligns fairly well with our results. Had the Vepr’s barrel failed with the next magazine or two, it would almost exactly match the prediction based on the efficiencies of the two respective rounds. Now, this ignores the slightly heavier contour of the Vepr’s barrel, so it’s possible that – gas block alignment discounted – the rifle could have failed somewhat later.

I’ll have to differ with Eric in his assessment. The Vepr’s excellent performance doesn’t so much prove that AK-pattern rifles will work until Judgement Day so much as it proves that the heavy contour CHF chrome-lined barrels Molot uses have excellent thermal resistance properties. This makes sense, as the Vepr is itself based on the RPK automatic rifle!



Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He can be reached via email at nathaniel.f@staff.thefirearmblog.com.


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  • Josh d

    The suggestion that the relative barrel wall thicknesses are contributory between the ar and vepr is silly.

    The ar15 wall thickness at hanguards is 95% of the diameter of the projectile while the vepr wall thickness is 77% of the projectile. So the ar15 had a heavier profile barrel relative to the size of the projectile.

    The ar15 had a free floating barrel with a very open handguard which provides for better barrel to air heat dispersion. In contrast the heavier handguard of the vepr increased its rate of temperature increase over the ar due to its profile and it catching fire later in the video.

    Either way, neither weapon was designed to do what the tests put them through and neither represent the classic archetypes of the weapon systems.

    Great fun.

    • Stuart Hunter Keough

      Looks to me like he was saying absolute wall thickness, you said relative. Anyways the math makes sense to me.

    • Relative wall thickness doesn’t matter, since what we’re worried about is the barrel’s thermal mass.

    • Josh d

      The ar didn’t have plastic heatsinked handguards, carbine gas system, and an m4 profile barrel, using it as a standard by which to compare weapon systems is unfair in a pure testing model.

      The vepr also was not built to standard ak47 configurations with the barrel, handguards and muzzle device. It too cannot be used as a standard model for pure testing purposes.

      The test wasn’t a pure test between the weapon systems, so seeking for the largest contributors to failure/success and suggesting it made for unfair testing criteria is the silly part. Neither were standard, but it is my contention that with the positives working for the ars heat dispersion, and the negatives for the vepr, we can surmise what the standard configurations of the weapons would have done relative to one another.

  • iksnilol

    Silly American, rifle of MOTHERLAND never fail. It only rests after enemy pigdogs have been buried under a MOUNTAIN OF LEAD!

    Also, shouldn’t 5.56 heat up faster since less air can go through the bore + higher pressure? My understanding of physics is pretty basic I’ll admit.

    • Joshua

      5.56 also heats up faster due to the higher pressure loads and faster bullet velocity which causes higher cyclic rates than the AK-47 gets with 7.62×39.

      • iksnilol

        I was thinking it would. Like I said, basic understanding of phyiscs but I reckon higher pressure = more heat?

        • Joshua

          Yep. It’s sadly one of those things.

          If we ran 5.56 pushing 45,000PSI of pressure the barrel and other parts would last a whole lot longer and take longer to heat up, but most 5.56 run closer to 55,000-58,000PSI which causes more heat and higher cyclic rates(unless designed to combat that).

          • iksnilol

            Hmm

            Wonder how longer the barrel would last then? Was thinking that’d be one of the advantages of long cartridges such as 30-06. Also the advantage 6.5×55 has over .260 remington, you can get the same performance for less pressure.

          • Joshua

            I think a 5.56 AK would interesting see how it performed in a similar test using high pressure ammo.

            Supposedly barrel life would be extended in using a lower pressure round.

          • iksnilol

            That’d be an interesting experiment. Two identical (save for caliber) AKs fired with the same type and brand of ammo together with the same firing schedule.

          • BrandonAKsALot

            The Vepr barrel is also cold hammer forged vs the Faxon barrel which is not. While it’s not going to change how much heat is absorbed, the barrel will be able to take a little more punishment and wont deform as fast.

          • buzzman1

            Longer cartridges make for slower cyclic rates and more feeding issues.

          • MPWS

            Make it more like 60-63kSI for 5.56. I have seen factory performed test results. It was also during endurance test, but not M16.

          • With a hot barrel like that, both 5.56 and 7.62×39 will likely be producing chamber peessures above 70,000 PSI.

          • Rick5555

            Well a 4140 barrel is rated to 100k psi and a 4150 is rated to 110k psi. Both barrels are usually proofed (tested) at 70k psi.

          • At low temperatures. At high temperatures, the maximum pressure rating drops quickly due to the change in material properties.

    • Kivaari

      Friction.

    • buzzman1

      The AKM the soviet army used was not the quality of the VEPR nor did they have the thick barrels.

  • Don

    Like the author pointed out above, come back with real results using like for like. The article states the rifle was customized by Copper Customs, so what did they customize? Was this an AK clone that used the same mil thickness sheet metal on its receiver as a true AK? If not your comparison is moot… Anyone can build and or modify a firearm to best another…

    I want to see a true test using the actual field rifles, not modified clones. Go pull an Afghani AK and a US M16/M4 (Whatever version they are using there) off the same battlefield, and using the same exact ammo used in the battlefield, and test them… Not only test their endurance but test them for accuracy during the endurance testing as well. I don’t care how long your rifle lasts, if it can’t hit the broad side of a barn it is useless.

    • Zippo

      come on guy, i’m sure m4/m16 can hit the broad side of a barn.

      • Don

        Hee-Hee-Hee..

      • iksnilol

        i guess, if you stand inside the barn 😛

      • Kivaari

        ARs are accurate rifles. More accurate than the AK. BIG BUT, the AKs come with crappy sights. Throw a Valmet or Galil aperture sight in the mix, and they shoot similar groups. The AR is much easier to “accurize”. Grab a rifle off the rack, and either one has the ability to fire good groups, based on the skill of the shooter. People call the Winchester M94 inaccurate, except if an aperture rear sight is used, all of a sudden those inaccurate M94s will do minute of angle. Those claiming the 7.62x39mm is an inaccurate round, just have not shot them. Chinese military issue 7.62mm was the most consistent military ammunition I have ever tested. It actually matched the specifications to within 7 FPS in a 20″ Yugoslavian M59/66A1.

        • Esh325

          While I have shot 7.62×39 AK’s with sights out to 400 yards and hit man sized targets, but the trajectory of the round makes it a real challenge. So I think the inaccuracy thing is at least partially true. I think sights have become less relevant since mostly everybody that goes into combat and has access to optics uses them. I suppose if you took your most accurate AK and AR in the same caliber, the AR would probably be more accurate, but I think after a certain point accuracy gets redundant for a combat rifle.

          • buzzman1

            Guys, Your arguments are moot because Soviet combat doctrine was you blow up an objective, then roll over it with tanks and APCs/AFV’s, discharge troops and they shoot at whatever moves on full auto fire at relatively close range. The soviets did a lot of city fighting which negated the necessity of long range fire.

          • Esh325

            They did also have SVD’s and PKM’s, but I think having a round that was more accurate and at least a bit longer range was at least of a bit of concern for the average rifleman, they went on to replace the 7.62×39 with the 5.45×39 after all.

          • buzzman1

            It was doctrinal change. The Russians have ammo dumps full of 7.62×39 that they have forgotten. The 5.54 gives them a longer stand off range, a flatter shooting round, more accuracy at range and just like the 5.56 the weight per round is substantially less so the soldier can carry more.

            The soviets and now Russians are suffering a population crash and less than 1/2 of the young men are physically able to serve in the military. That means they can’t just send human waves at the enemy to die like they did in WW2. Just don’t have the people anymore or the military capabilities. Just as the Taliban in Afghanistan engagements start at long range (beyond rifle) then with rifle. The newer Russian rifles supposedly are accurate out to 500 meters (I’ve never shot one) but I don’t think the average Russian soldiers are any more capable to accurately engage a target at beyond 200 meters than ours are.

    • iksnilol

      Somebody is peeved their favorite rifle didn’t win this round 😛

      I wonder what mods were made to it, though? You’re right in that you can’t really hotrod a rifle and then say “See, this kind of rifle is better”.

      • Joshua

        Wasn’t the FAXON barrel also a stainless steel barrel?

        I can’t remember but if so SS is far less durable of a barrel material.

        • iksnilol

          I don’t know. Should look into the theme.

          How’s the accuracy with the barrels as well? I’ve heard that stainless or chrome plated is less accurate.

          • Joshua

            From what I’ve seen some of the most accurate barrels are button rifle SS barrels, which is what I have always heard is the point to SS barrel.

          • iksnilol

            That’s whta confuses me. Since all the precision/target guys I know avoid stainless like the plague. Considering these guys outshoot most rifles on this planet I sorta trust them.

          • Don

            Well, I know some of the top precision shooters use Proof Research barrels. They are carbon fiber wrapped stainless barrels, I know I have one.

          • iksnilol

            I’ve always been interested in those hybrid barrels. Thin steel barrel wrapped in CF or aluminium.

            How does it work for you?

          • Don

            I’m still in the testing and deciding phase. I’ve had mine for about 4 months now so I haven’t had it long enough to come to a long term conclusion yet. The barrel definitely stays cooler just as they claim it does. And it definitely hits 1/4 moa or less all day long at 100 yds., it definitely tightened up my grouping. Proof Research said the 20″ .308 barrel I have shoots best with 168 grain ammo, so I am still testing ammo to see what it shoots best with.

          • iksnilol

            quarter MOA!?

            How’s the weight on it? I am kinda thinking that a 308 long action Mauser with a barrel like that (thinking 18 inches) would be the bees knees here in Norway. Cheap and effective.

          • Don

            Cheap, I don’t know about that but it is definitely more effective 🙂 🙂 Its a bull barrel so the weight factor was one of the big reasons I went with the hybrid. It is about 65% lighter than the same barrel being made of stainless. 1/4 MOA, think of the size of our dime or less. The barrel definitely shoots way more accurate than I can. I have just started taking it out to 300 yds., that is where I am trying all the different grains and bullets to see what it likes best.

          • iksnilol

            Mausers are essentially Mosins here in Norway. So I am thinking of buying a Mauser, chop the barrel down and thread for a suppressor (+ bottom metal that allows me to use AICS mags). Then when the barrel is eventually shot out get one of those lightweight bull barrels.

            So it should be relatively inexpensive compared to other rifles.

          • Don

            Now that will be an interesting but fun rifle. You’ll have to post pictures of it when you buy it and finish it. I don’t think I have ever seen one of the older rifles suppressed yet.

          • iksnilol

            Not really unusual in Norway considering suppressors are completely unregulated. I will find some picture for you:

            https://uploads.disquscdn.com/images/eff0bbe9d8ce4e2bf02a761b94a54ffb19b9fa8e0fe7926caf8ff7f9708a7dea.png

            That one is basically rebuilt, it started out as a 30-06 M98 Mauser, then it got converted to 6.5×55. Only 5.6 kg weight with all the stuff.

            https://uploads.disquscdn.com/images/9a7846af8353574dcdf4fb309238672c8acf9b319a3b9dc7c77f19081f0495ac.png

            Synth stock and some other small modifications in addition the homemade suppressor.

            https://uploads.disquscdn.com/images/7f15f9759b3993e99735aa4d39b875ef96c4cd3dddf0dfe604c281464c097461.png

            Swedish M96 in 6.5×55. This one is mostly stock except for the scope and suppressor.

          • Don

            Sweet looking rifles, but LONG suppressors 🙂 You guys are lucky that the suppressor isn’t regulated, we can only hope to get there one day.

          • iksnilol

            Not as long as they look like. Most of them go 10-20 cm (4-8 inches) behind the muzzle.

            The homemade suppressor is long, I’ll give you that. 😛

          • Kivaari

            The barrels worth having are very expensive. A good Mauser M98 action is an obvious better choice than the M91/30.

          • iksnilol

            Clunky bolt action is clunky. Any rifle is smooth if you bother to polish it up.

          • ostiariusalpha

            That is all kinds of wrong. Precision competition shooters favor stainless because it’s higher elastic yield strength is more resistant to throat erosion and other wear, so they last for longer overall round counts than Chrome-Moly barrels before precision starts to drop off. The most precise barrels are widely acknowledged to be cut-rifled barrels, like the kind that are painstakingly made by barrel manufacturers such as Krieger. Button rifled barrels are considered the least precise barrels made (next after badly cold-hammer forged barrels) due to the stress that the buttoning process can put in the steel. Lots of shooters go with button rifling anyways because it’s inexpensive and, occasionally, they don’t have too excessive amounts of stress in the barrel to negatively effect the overall precision.

          • micmac80

            Only reason stainless is good for in barrels is copper fuzing to the barrel surface that could hapen to chrome molly . And general maintenance (rusting)

          • ostiariusalpha

            No, those are just other reasons that stainless is superior for precision rifle barrels. If you’re putting in strings of rapid fire like in 3-gun or other tactical shooting competition where you aren’t needing 1/4 inch precision, then chrome-moly is best. There is also a decent amount of evidence that stainless has better general harmonics than chrome-moly.

          • Stainless steel for barrels is 400 series stainless which is not actually rust resistant. It is actually WORSE for rust than 41XX series steels.

          • mikee

            Absolutely correct. I’ve been in the high power game for decades and having used both stainless and chrome molly barrels – stainless wins hands down for accuracy and longevity.

          • mikee

            Rubbish! Look up FTR, Palma, F-Open class highpower shooting competitions. Then look up Krieger, Bartlein, PacNor, Trueflite and other custom barrel makers. You will soon discover that the majority of highpwer competitiors use stainless barrels exclusively.

          • Kivaari

            There is stainless steel and then there is stainless steel. Use the correct SS, hammer forged and fitted with care will give long life. Too many shooters want a SS barrel, and end up with a lower grade rifle while searching for the lower cost. The lower cost SS barrels give you what you pay for. Serious shooters step up and buy the best. If they don’t they don’t get great scores. Like having an AMT Hardballer stainless steel M1911. Absolute junk, that cost more to the customer, but leaves the customer with junk.

          • mikee

            Your response also applies to chrome molly barrels as well. There is little if any cost compromise using stainless barrels. You get what you pay for in all manner of things! Being in the high power game for decades I would not contemplate using a chrome molly barrel for competition for all the reasons and then some as has been mentioned by contributors on this post.

          • iksnilol

            I was mistaken. I’ll admit that.

            What I probably meant was chrome plating vs unchromed. I know unchromed barrels are more accurate than chromed ones.

            Stainless is easier to work with, isn’t it? So it shoudl probably be easier to make accurate barrels out of it.

          • Rick5555

            A Stainless barrel is more accurate than a Carbon barrel. However, Stainless heats up faster. There’s always a trade off. The best accuracy will come from Single Cut Rifling,, then Button Broached and finally Cold Hammer Forged. Though a Cold Hammer Forged barrel will be more durable. They aren’t as accurate as a Single or Button Broached Rifling. A fair comparison would be to use a 4150 CMV chromed lined barrel. To the CHF AK barrel. As well as, both rifles are shot at the same time. The outside conditions will play a factor in this too. When Eric did the AR it was summer time. This AK was done in the winter. Which there was at least a 30 degree variant in outside temps……………………………………………………………………..
            All Eric did was a torture test for entertainment purposes. There was no scientific testing done at all. Which proves nothing.

          • micmac80

            There is no advantage to accuracy SS vs Chrome molly. None what so ever.

          • Incorrect. Stainless actually machines much better in most processes producing finer rifling than 4150. However, with modern manufacturing, the difference is negligible (but still present).

          • mikee

            Correct! Stainless barrels are easier to tune, hold their accuracy sweet spot longer and are more accurate in general for high power competition. Stainless barrel technology and metal formulations have come a long way in the past twenty years. The caveat is the ability of the rifle/pistol smith to chamber and crown the the barrel precisely.

        • Yes, it was stainless and correct, it is not as “durable” in terms of extreme high-heat scenarios.

        • micmac80

          SS has issues with heat conductivity that is crucial to such test.

        • Kivaari

          Carbon steel from my experience is better than MOST stainless steels used in guns. Given a choice a S&W M13 is a better gun than the M65.

      • Don

        Not at all 🙂 I’m a lover of all firearms. I’m just sick of people comparing apples to oranges, its done big time in the auto industry as well. That and the entire “My rifle is better than your rifle” argument has gotten so old.

        • Rick5555

          I agree with you. All Eric and his channel accomplished was the entertainment factor and that’s it. The channel is fully aware of what they were subsequently doing. There was no science conducted in any of their purported testing. I watched for entertainment value only. And curious to what BS Eric, was going to spew too.

          • Don

            I laughed when he said that the AK barrel outlasted the AR barrel BIG time… I had expected him to say it beat it by several hundred rounds when he mentioned that. What did he say, there was a 68 round count difference? That’s not a huge difference.

          • displacer

            65 rounds difference, and I’ve seen a similar government trial where the new M4A1 did 911 rounds before it’s gas tube burst and the test team continued to hand-cycle and fire rounds. The AR successfully fired about 93% of what the VEPR did before it failed, and it was using a medcon button-rifled stainless barrel meant for affordable accuracy instead of the VEPR’s thicker CHF chrome-lined chromoly barrel designed for sheer durability in the RPK’s LMG role.

            That dude is a huge AK fanboy and it shows, he acted like those extra 65 rounds out of a better barrel. I like both ARs and VEPRs and rather than proving one better than the other these doofy little tests of his prove that with a sample size of two, a mid-tier AR and top-tier AK both stop going bang somewhere between 800 and 900 consecutive rounds

          • Marcus Toroian

            You also have to remember that the AR barrel failed catastrophically, bursting out the side. This one just warped enough to make charging it very difficult.

          • The AR barrel failed catastrophically where the thermal mass of the barrel was least, that is, right behind the gas block.

            The Vepr’s barrel had no such weakness.

          • We heart your explanation.

    • Darrell

      The VEPR’s receiver is much thicker than a standard AK’s, half again IIRC. As mentioned, the VEPR is derived from the RPK machine gun.

    • Kivaari

      Changing the stock, sling mounts and likely the full-auto conversion. VEPRs come in looking like a sporter, not a GI configuration. Just how would they get a new AKM out of Afghanistan? This was a great test. Just like the AR test they did. You seem to be putting them down because they used a nicer example. After running the CAI rifle into the ground.

    • Esh325

      I’m fairly certain all they did was just add a new finish,smooth out the edges,convert it to full auto, and make it accept standard military magazines. So it’s not an unfair test at all.

  • micmac80

    hammer forged chrome lined vs button rifled.

    In any case this is not what rifles are designed to do .

    • This would be far more interesting, but its difficult to draw conclusions based on the differences in treatment. You would actually want to run two separate tests:

      1. CHF vs Button/Cut/Broach
      2. Chrome vs. QPQ vs. Standard Barrel

      • micmac80

        For starters CHF and Button rifled would do

        No one really uses cut rifled barrels in service rifles

        • One can use any of the three. The key is to use a rifling technique that is not forged. In terms of the effect on steel, cut, broach, or button (stress relieved) are all good enough to test.

          • micmac80

            True to a degree but button rifled still compacts the bore surafce upon rifling to a degree , while cut doesn’t.

          • It does, until stress relieved, when the barrel steel resets into its current position, removing the impact of the compaction.

            Using a non-stress relieved button barrel is typically not wise. Groups will deviate significantly once the barrel even gets warm.

  • Vitor Roma

    Now I want to see a PWS being tested like that. It is an AR with a long stroke piston.

  • Zugunder

    I wonder if he had shot it upside down would that allow him to run it a tad bit longer, to the point of complete barrel failure?

    • The barrel “droop” is more to do with the gas thrust and gas piston hitting the gas block than the weight of the barrel. Steel, specially ordnance steel, would have to be at such a hot temperature that it would not hold the pressure of firing before it would droop due to gravity.

      • Zugunder

        That makes a lot of sense actualy. Thank you.

  • SP mclaughlin

    >no more VEPR Molot imports
    >destroying one
    mfw

    • iksnilol

      Just the barrel, you can replace it easily enough.

    • Alexandru Ianu

      No more Izhmash imports – Molot stuff is not under embargo last I heard.

      • displacer

        Yeah, they don’t seem to be produced in the quantity that the Saigas were in the past but they still seem to be coming in. The price on VEPR-12s has been holding steady at about $800 with 100 rounds of free ammo for a while now and I’ve seen several retailers sell out then get more in stock. The rifles are a little more scarce but they too come and go while staying between $800-$900

  • MPWS

    Study (perhaps unintentionally) omits the rate of natural cooling (be it thru convection or radiation) into atmosphere. More open concept design of AK will probably perform better on this score alone.
    AR likely tends, due to its enclosed construction, to trap the heat. Since there is metal to metal connection on both (barrel to receiver), this is in reference to entire rifle, not just barrel. Also, colour of finish has some effect in heat dissipation.

    • MPWS

      Another item not to be ignored is bore size. With bigger bore you have more of pumping/ cooling air flowing thru barrel. So it will be relation of bore and bbl length ratio which will affect the result.

  • A solid starting analysis, but does not take into account all variables.

    The Faxon barrel used was stainless steel, not mil-spec 4150. Further, it is not take into account the surface area of the barrel and how it relates to cool-down, as the calculations above assume no heat is exhausted from the steels.

    Stainless is not as thermally conducive as 4150, retaining heat longer by not exhausting it across the air, causing failure earlier. Further, the wall thickness is similar, but due to the smaller OD of the barrel, there is less material to absorb the heat and less surface area for it to exhaust it.

    • I also wonder if the lack of chrome-lining of the barrel caused the rifling to wear faster, which would have reduced friction heating, adding to the number of uncontrolled variables.

      • Yes and no. At base temperatures, QPQ is actually less resistant to bullets (less friction) than Chrome, yielding higher velocities.

        At “low” to “medium” temperatures, Melonite (and most other Nitrocarburization processes) have roughly the same wear characteristics. Once past 1000 degrees, Chrome has better abrasion resistance, as it is not part of the base steel, as Melonite is.

        For an infantry combat rifle, chrome is overkill, especially with the reduced accuracy potential. It takes more than an infantryman can carry to heat a barrel to that temperature, with magazine changes. QPQ increases velocity, has higher corrosion resistance, and is more accurate (all things being equal)

        However, for a true machine gun, chrome is the way to go, due to this extreme high temperature performance where accuracy is secondary to volume of fire.

        In the case of the stainless barrel at extreme high temperatures it becomes more pliant than 4150, which would lose rifling faster, more a function of base temperature than the bullets or choice of coating.

        • For an infantry weapon, the accuracy disadvantage of chrome-lining would be totally insignificant with regards to the total system effectiveness.

          QPQ is more corrosion resistant, that’s true.

          • Yes, if that’s all that is being evaluated, but on the whole considering cost, velocity, accuracy, corrosion, etc, QPQ is the better choice for most applications (again barring light and medium
            machine guns).

        • Kivaari

          I’m pretty sure the reason chrome lining is in rifles in military service is to stop corrosion. Like the US Army’s issues with M16s in Vietnam. Pitted bores and chambers were bad things. Every general issue military rifle should have chrome plating.

          • Not quite. For example, the Garand was not Chrome Lined. I am sure Nathaniel F. would be able to go into the details why at some point later.

            Corrosion resistance, reducing friction in a chamber, etc are all reasons to line a barrel. Chome was appropriate through the early years of an M16, as Nitrcarburization was not yet invented or perfected.

          • Chrome-lining was simply not a standard process for military weapon barrels at that point.

          • Esh325

            People like Nathaniel might disagree, but for what ever reason all the non chrome lined weapons of WW2 didn’t appear to have the same issues to the degree the M16 did with its barrel. I suspect the M16 having .22 caliber bore with a relatively high velocity projectile,being a rapid fire fully automatic rifle with a 20 or 30 round magazine might have made the M16 more suseptible to problems with the barrel than previous generation weapons making a chrome lined chamber and barrel absolutely necessary. I could be wrong though.

          • Kivaari

            Because we simply didn’t do so. Soldiers were trained to clean their rifles. Bore cleaner designed to stop corrosive priming damage was standard issue.

          • Actually, the M1 rifle had quite a bit of corrosion issues in the South Pacific. Official Ordnance Department histories of WW2 confirm it, as do first-hand accounts like “Ordnance Went Up Front.”

          • Kivaari

            The M1 rifle experience in Korea was not all roses either. Sub-freezing temperatures lead to stoppages and fractures in the RHS receiver rail. A technical manual circa 1955 (not a field manual) discussed significant problems with the Garand. It was serious enough that the search for replacements were well underway from WW2 forward. The M1 rifle and M1911 have a mythical haze around them, where people think they were flawless performers. They were not.

          • People like U.S. Army Ordnance circa 1944-1945 might disagree…

            Materials to clean and oil the small arms were much in demand. Cleaning and preserving (C&P) materials had been in short supply to begin with. Many of the M1 rifles had been issued without oil and thong cases. Often when the men had the cases they simply threw them away to lighten the load they were carrying. By 3 December the shortage of gun oil, small individual containers for oil, brushes, cleaning rods, and other C&P items was serious enough to effect operations. One combat officer, observing that the first thing the men stripped from the Japanese dead or wounded was the neat bakelite oil case they carried, reported that gun oil was ‘very precious and always short.’ Urgent messages characterized the condition of small arms at the front as ‘deplorable’ and ‘terrible.’

            – The Ordnance Department: On Beachhead and Battlefront

            The M1’s were going to ruin for lack of cleaning in the holes up front-the poor guys did not have anything to take care of them with, and often were not in a position to shoot them often enough to keep the barrels clear of corrosion (grass won’t grow on a busy street-regardless of the corroding primer compound, if a .30-06 barrel gets a bullet through it every six or eight hours it will stay in pretty good shape). As a result of the fouling of gas cylinders and pistons, a large percentage of our semi-automatics were becoming singleshots.

            – Ordnance Went Up Front

          • Kivaari

            What? I didn’t mention the old rifles. I mentioned the M16 in the Vietnam era. Other nations were ahead of the US in regards to chrome lined bores. I had 2 Japanese desperation 7.7mm rifles with chrome bores. The US should have led the pack.

          • FWIW: Stoner 63 barrel were nitrided.

          • ostiariusalpha

            Yeah, but the Stoner 63 is an OOPArt from an alternate dimension.

    • ostiariusalpha

      Correct. CMV 4150 has an elastic yield strength of 380 MPa and an ultimate tensile strength of 730 MPa; 410 Stainless has a yield strength of 415 MPa and tensile strength of 450 MPa. The higher elastic yield of the stainless can withstand the intermittent firing of magnum rounds better than the 4150, but it’s low UTS makes it inadequate for long strings of firing.

    • Dog Molotov

      Faxon I’m glad that you’re back in this conversation to break down the science for us. To be fair I was still impressed with the performance of your barrel in the test– considering the handicap.. I’ve always felt like the AR burnout video was an unfair and an unwanted PR hit to your product

      • A pleasure to be here, as always.

        We actually do not take the burnout video as a PR hit, as the barrel performed fantastically for what the barrel was – we just use it as a learning opportunity for our customers to understand the various things that go into a barrel.

        • Dog Molotov

          Stay Classy Faxon!

  • Bill

    Maybe I missed a meeting, but what’s the point? ANY barrel will fail eventually, faster if it is abused, as will any mechanical device. It doesn’t really mean anything about the life of the barrel or weapon in actual use, because it is the constant, sustained fire that is deliberately pushing to failure that destroys the barrel/gun. It’s no different than running an engine past redline for as long as possible to see how long it takes to throw a rod.

    Maybe during the zombie apocalypse this will be useful information, assuming that the user is backed into a corner, has someone loading mags for him, is a perfect shot and is being attacked by no more than 895 zombies, continuously.

  • Don Ward

    Yawn.

    I’m sick of these sort of stupid and generic “Herp, Ahma ruin a perfectly good gun” videos.

    • andrey kireev

      I’m sick of these sort of stupid and generic “Herp, Ahma ruin a perfectly good comment space”

    • ostiariusalpha

      Lance hasn’t even commented yet. What are you trying to do, steal his thunder?!

    • Bill

      As I said previously, they basically don’t prove anything, other than abusing any firearm sufficiently will cause it to burst into flames and generate youtube views. I cannot think of anything learned from this, other than don’t expect a rifle or carbine to fulfill the role of a purpose-built machine gun.

  • Derp

    Still waiting to see the basic statistics that were collated since those were not “statistics”.

      • Derp

        Exactly, correct definition. What is the sample size you used? Barrel specs are not statistics. The round count to failure would be 1 data point.

        • Exactly how are barrel measurements not data?

          • Bill

            If this is an actually “test,” there should have been a hypothesis, a null hypothesis, a control, an identification of known independent and dependent variables, a stated testing protocol and not just blasting away until the gun croaked.

            Is this a test of barrel dimensions or mean rounds between failure? It can’t even been that, because as Derp said, it’s a sample of one.

          • I am confused, Derp was saying that the measurements I listed in the text body were not “statistics” (he’s correct that they weren’t the result of statistical analysis, but words have many meanings).

            The test conducted in the video itself is essentially fooling around, and definitely not scientific.

  • Bacon Chaser

    Heat treated wooden furniture…

  • Taofledermaus

    All I can say is I really miss Barry.

  • Simcha M.

    Please don’t do the torture test to my beloved Galil, I beg of you………………………

  • Kivaari

    Impressive. When it shows barrel wall diameter is that just a typo, for the thickness?

  • Esh325

    As far as AK’s go, I don’t think you could really do better than a VEPR in this type of test. Perhaps a 23 inch RPK barrel might fair better, but I could be wrong. I don’t believe people in combat carry 895 7.62×39 or 5.56×45 rounds anyways, and they wouldn’t be able to go through it that fast in combat like in the video. So it really it shows the AK can be even more reliable than it has to be in many situations. It would be interesting to see the test done with a quality AKM or AK-103 like rifle because most AK’s don’t have a RPK receiver and barrel. I hope he chooses the MR556 for the piston test because it’s considered the best out there for op rod guns. It would be interesting if he did a test Heavy barrel M4 profile, I suspect it would do better. A 20 inch M16 would also be an interesting test as I think they would fair better in full auto because of the longer barrel and smoother operation because of the longer tube and heavier buffer.

    • Kivaari

      The A1 “pencil barrel” would likely fail faster than current barrels, simply because the larger heat sink. These test ’til they break videos are great. I just hate to see such good guns ruined.

      • Esh325

        An A2 profile M16 would be better for the test as it’s a newer style. I suppose as long as the receivers aren’t compromised, they aren’t really ruined. Barrels,handguards, and other parts can be replaced.

        • ostiariusalpha

          Meh, the A2 profile is identical to the A1 till you reach the gas block; having more steel in between the
          gas block and muzzle is negligibly beneficial enough to be functionally useless. There are 20″ barrels out there that have the same diameter as the thick section of the A2 all along their length; there are also 20″ HBARs out there. Any of those would soak up heat like a champ.

          • Esh325

            Yes, you might be right about the heat. Would still be an interesting test to see though.

          • Kivaari

            I recently sold my HBAR so I could afford to do an SBR. The Bushmaster HBAR was one of the best shooting ARs I’ve ever owned. It was not floated, just the standard fore end. The biggest improvement that allowed me to shoot it so well, was installing a Geiselle SSA hammer and trigger. I use them in all my ARs, and it helps lob off 1 MOA.

          • Esh325

            Certainly there is a lot of accuracy potential in the AR15 even without using a free float handguard.

    • Bill

      An RPK, being a LMG, had better do better. ANY rifle/carbine undergoing gratuitous mag dumps SHOULDN’T do better.

      • Esh325

        Well this VEPR is basically an RPK, it’s just the barrel is the 16 inch AK length and not 23 inch RPK length.

  • smartacus

    outSTANDING!!
    i’m SOOOLD.
    Hugo Schmeisser’s brainchild was the best invention ever stolen and historically recredited by the Soviets

  • Esh325

    Was the M16A2 modified to fire fully auto I wonder? Is the M4A1 they used have the standard profile or the heavier barrel? I’m surprised the M16A2 barrel didn’t last as long or longer than the M4A1 barrel.

    • ostiariusalpha

      Since no one else seems to be interested in answering your questions, I guess it’s up to me.
      Yes, the M16A2 upper was on a full auto lower, and that was how it was tested. The M4A1 carbines at the time of the test (1996) used the same slim profile under the handguard as the M4. This was later altered to the heavy SOCOM contour to deal with the issue of overheated barrels bursting.
      It isn’t necessarily too surprising that the short barrel did a bit better than the long one, despite there being more steel in the M16A2 barrel to soak up heat. Firstly, the bullet has more barrel length to travel through on the M16A2, which means that the superheated gases pushing on it are trapped in the barrel for a bit longer to transfer more of their intense temperature to the steel. Secondly, the thicker segment of the barrel after the gas block, which soaks up heat far better than the pencil contour under the handguard, is further away from the chamber on the M16A2; it has less capacity to pull heat from the hottest part of the barrel than the shorter M4 & original M4A1 barrels. Lastly, as the metal starts to yield from heat fatigue, the heavier front end of the M16A2 is going to put more pressure on the most weakened part of the barrel than the short M4/M4A1 barrel has to deal with.
      In conclusion: pencil barrels are great for lightweight rifles if you are using them for plinking or pest eradication, but they suck for actual military use.

      • GG

        Standard load is “only” 7-8 mag. Barrel rupture occurs after 16 mag fired in 4 min. For me is a good result.

        • ostiariusalpha

          Yeah, it’s not too shabby. But you know that plastic A2 handguard would be getting mushy after the 6th mag and the accuracy would have gone to crap after the 2nd.

  • UnrepentantLib

    Just a suggestion for a future experiment. The Battle of Wanat was infamous for M4’s, as well as other weapons, failing. If you can figure out the time lines and number of rounds fired for several of the weapons that failed, try to recreate it, maybe with some alternative weapons, like the HK416 or other piston drives, running parallel. Could be interesting (if a bit expensive.)

    • Brian M

      I actually stumbled across a really great forum post which did a writeup of it and what was written about it later, so I’ve reposted it here. Thanks, Google!

      __________

      The battle of Wanat, depending on who you ask, it was a disaster caused by weapons failing because they’re junk, or the disaster came from the army who couldn’t bother to take even the simplest measures to perform competently, especially in terms of teaching its soldiers to control their fire.

      Well, I did some math regarding what the interviewed soldier said about how much he was firing his M4.

      ““My weapon was overheating,” McKaig said, according to Cubbison’s report. “I had shot about 12 magazines by this point already and it had only been about a half hour or so into the fight. I couldn’t charge my weapon and put another round in because it was too hot, so I got mad and threw my weapon down.””

      Let’s do a bit of math.

      The Army Study guide says that the maximum sustained effective rate of fire of the M4 is 15 rounds a minute. Because McKaig said that he fired about twelve magazines each holding thirty rounds during the first half hour of the fight. Multiply the 30 rounds in each magazine by 12, representing the number of magazines. This tells us that it took him roughly 30 minutes to fire off 360 rounds of ammunition. So the total volume and time is 360 rounds over 30 minutes.

      Now in order to find out a more useful rate of fire, divide the number of rounds by the number of minutes. This comes out to 12 rounds a minute, or approximately one round every five seconds.

      Remember that the US Army publishes that the M4’s sustainable rate of fire is 15 rounds per minute, or one shot every four seconds. Now, since it has been established that McKaig fired 360 rounds over 30 minutes at a rate of 12 rounds a minute, or one every 5 seconds. This is a full 25% slower than the proscribed maximum of 15 rounds a minute, which comes out to 1 round every 4 seconds. In order to McKaig to have brushed up against the maximum sustained rate of fire during he 30 minute episode he describes, he would have needed to have fired 15 rounds a minute for a solid 30 minutes, which comes out to 450 rounds in all, which is again, a full 25% more than he fired.

      McKaig’s M4 failed in spite of him sticking to the proscribed limits of the platform’s limitations. He was not running his assault rifle like a machine gun; he was firing controlled, paced shots well within the stated limitations of the platform.

      And this wasn’t the only case of weapons failing in spite of being handled properly according to Army guidelines.

      “Some GWOT and U.S. Army veterans queried by the author have suggested that this could have been caused by improper weapon cleaning. However, numerous Chosen Few NCOs interviewed for this study have been vehemently adamant in stating that weapons were meticulously and regularly cleaned, and rigorously and routinely inspected by the chain of command. Other GWOT veterans consulted have noted that the high rates of fire sustained during the two hour intense engagement phase at Wanat could possibly have contributed to these failures. However, numerous weapons failed relatively early in the engagement (particularly a number of M-4 rifles and at one SAW at the mortar pit), and in any event the maintenance of cyclic rates of fire was critical to restore fire superiority, and to prevent positions (particularly at OP Topside) from being overrun by determined, numerous, and hard pressed insurgent assaults.”

      Source: Defensetech

      “Army officials say that when properly cleaned and maintained, the M4 is a quality weapon that can pump out more than 3,000 rounds before any failures occur.”

      “Cpl. Jason Bogar fired approximately 600 rounds from his M-249 before the weapon overheated and jammed the weapon.

      Bogar was killed during the firefight, but no one saw how he died, according to the report.”

      The M249 has a standard combat load of 600 rounds stored in 200 rounds drums. Its cyclic rate of fire is listed as between 650-850 rounds per minute. A rapid rate of fire is 200 rounds per minute, but a sustainable rate of fire is 100 rounds per minute. Now, it is highly improbably that the M249 used by Bogar was fired 100% cyclically, owing to US troops being trained to be careful with their fire, but more importantly, reloading would eat up rather meaningful amounts of time. Thirdly, failure tests of the lighter-barreled M16 and M4 have turned up results stating that in order to get catastrophic overheating failures, it takes approximately 550-600 rounds to destroy an M4 barrel, which is much lighter and smaller than an M249 barrel, which means less ability to absorb heat from firing. So is an 11.5″ barrel M4 with a cyclic rate around 800 rounds per minute) going to really crap out from heat during rapid fire than an 18-20″ barrel M249 which is designed specifically to handle heat far better?

      “SPC Bogar fired approximately six hundred rounds at a cyclic rate of fire from his SAW when that weapon became overheated, and eventually jammed the bolt forward. SPC Stafford noted, “Bogar was still in our hole firing quite a bit. Then Bogar’s SAW jammed. Basically it just got way overheated, because he opened the feed tray cover and I remember him trying to get it open and it just looked like the bolt had welded itself inside the chamber. His barrel was just white hot”

      An open bolt machine gun failing from heat welding it up at the same level of fire as a closed bolt carbine? Seems unlikely unless the weapons are not really up to spec advertised, the amount of fire put out significantly differed from reports, or the army is being dishonest in its materials.

      Alas, there is no timetable to find out what happened and how to Bogar. All that is known is that his M249 failed from overheating and he was killed sometime later, most likely during a later phase of the battle because nobody interviewed saw him die. Regardless, it is a fact that his weapon failed, even if perhaps not necessarily being used in exactly the proscribed manner, but long before it should have.

      And here is confirmation that more weapons failed.

      “SG Phillips poured out fire, as recalled by another Engineer SPC loading for him, “…[SSG Phillips] went through three rifles using them until they jammed.”103. SSG Phillips recalled: “My M4 quit firing and would no longer charge when I tried to correct the malfunction. I grabbed the Engineers SAW [M249 5.56mm Squad Automatic Weapon] and tried to fire. It would not fire, so I lifted the feed tray tried clearing it out and tried to fire again. It would not.” SSG Phillips did not realize that SGT Queck had earlier attempted to fire this SAW, and it had failed at its first shot when a bullet jammed in the barrel. Queck had quickly discarded the SAW, swearing profanely in frustration that it was “f**k*d up!””

      TL;DR? What am I trying to say? Simple. Weapons at Wanat failed long before they should have, even in cases when they were not being abused beyond their limits.

      __________

      Yeah, so multiple M4’s and at least one M249 royally goofed at Wanat, and it wasn’t a case of the media latching onto just one guy having to deal with a couple of minor hiccups.

      • UnrepentantLib

        Thanks. That’s an interesting post. Something clearly doesn’t add up.

  • lowell houser

    Oh for crying out loud, the VEPR is patterned after the RPK, not the AK. It has a heavier barrel, beefed up trunion, and thicker receiver. In short, it’s built like a light machine gun, OF COURSE it did better.

  • Dan

    I like how he stopped when engaging the mag release with his thumb to instead use a full mag. And the heavy breathing/grunting noises. This guy is one of them people that no matter what he does will irritate me. He can crap gold an I will find it the most annoying thing anyone could possible do. And for some reason I keep clicking the video thinking it will be different

  • Dog Molotov

    I don’t know if someone brought this up, but wasn’t the AR-15 burnout with a stainless-steel non-chromed lined barrel? It also wasn’t using the thicker M4A1 profile as well.. I don’t recall..

  • Where is this chart from?

  • BrandonAKsALot

    Must be nice to wake up and think, “what kind of gun can I destroy today and accomplish literally nothing?”

  • C.

    What do the thermal efficiency percentages indicate?

    • How much energy is being used to propel the projectile forward. The rest is wasted, mostly via heating the barrel.

  • John

    You know, THIS is what I expected TFB to do when doing a mag-dump test on the HK-36. Maybe not to destruction, but certainly at least 200 or 300 rounds.

    As the song goes, this is how you do it.

    • I’m not sure what firing a G36 to destruction would prove… The problems with the G36 were expressed as wandering zero issues over short strings of fire, not that the weapons physically melted during shoot-to-failure tests.

  • James,

    I’m flattered, thank you.

  • Sam Green

    President Obama should hire Iraqveteran8888 to shoot off the excess rounds he ordered for Homeland security, out of the 1.6 billion rounds ordered over the five year contract in 2012, they estimate they will actually only use 13 million over that 5 year period.

    This ammo was purchased by that sly Obama to try to curtail supply to civilians.

    So that leaves 1.59997 billion rounds that Eric can melt barrels with.

    In 100,000 years or so, Eric’s great, great, great, great, great grandchildren can see if the 250 million rounds of ammo allocated to the Library of Congress back in 2014, that was ordered by President Obama, is somehow compatible with their pulse shock rifles.

  • Joshua Madoc

    “Pick an AR if you’re going to the city, pick an AK if you’re going out to the country…”

  • Mc Cain

    I love the smell of burning AK in the morning!

    I got a big kick out of this video, I was happy to see he wore a bit more eye pro than when he did the AR failure test, in which the barrel basically blew up in his face.

    The wood foregrip literally burning entirely off the weapon was particularly awesome.