Overheating an AK47 Barrel

[cormyr 0]

A seemingly simple question, let's see where this one goes: How many rounds of continuous fire would it take to overheat a typical chrome-lined 7.62x39 AK47 barrel enough to cause damage?

[Cobra 76 two 2,677]

LOL!

 

 

 

[cormyr 0]

yup. i've seen that one (hilarious) and plenty of others. wood catches on fire, smoke billowing, glowing barrels, yada, yada. i find it hard to believe that any barrel is indestructible. anybody have any info on this?

[Saiga_rom 91]

A seemingly simple question, let's see where this one goes: How many rounds of continuous fire would it take to overheat a typical chrome-lined 7.62x39 AK47 barrel enough to cause damage?

 

i would think this is a materials science question. wed have to know the exact material properties of the metal that composes the barrel, and how these strength characteristics change with temperature.

 

we all love AKs and know how reliable they are, but still, the accuracy would be compromised if someone were to continuously fire an AK until the rifling on the barrel is deformed

[cormyr 0]

ok, lets say 4140 forged steel, 1.2.2.2 MIL-STD-171 hard chrome bore.

[Saiga_rom 91]

ok, lets say 4140 forged steel, 1.2.2.2 MIL-STD-171 hard chrome bore.

 

do you know what type of heat treatment is done on the barrel after it has been formed? im looking at a table of material properties for 4140 steel, specifically tensile yield strength (thats fancy talk for stress where material deforms), and it varies from 61 Kpsi to 238 Kpsi depending on how the material was heat treated

[Saiga_rom 91]

actually, nevermind, what we really want to know is the material properties of chrome. im trying to dig up some information on it

[Saiga_rom 91]

i seem to be having difficulty finding the tables which show how the yield strength changes for this material as it increases in temperature.

 

basically though, wed have to know how much force it takes to push a round through an AK barrel, then divide this force by the contact area of the round with the barrel, which would tell us the stress exerted on the barrel as a round passes through it. then referencing the table of material properties, wed see what temperature our grade of steel would deform at for this calculated stress.

 

basically, it wouldnt tell us exactly how many rounds it takes to deform the rifling because this depends on how fast you fire the rounds, but it will tell you the critical temperature where the rifling's integrity would be compromised as rounds pass through it

 

note though, this approach neglects the effect of thermal expansion, as well as cyclic stress effects.

Edited March 23, 2011 by Cali_Armz

[cormyr 0]

Hmm. Sounds like the math involved in that equation goes a bit beyond my Calc 101 education lol. I did however find this quote online: "According to a book title "Legends and Reality of the AK" the testing of the prototypes at that took place at the Izhevsk factory, that during the durability test each prototype had ran through more the 13,000 rounds before testing was terminated because all on hand ammunition had been fired."

 

Quite an impressive statement. I just wonder how long it took to go through that many rounds.

[Saiga_rom 91]

Hmm. Sounds like the math involved in that equation goes a bit beyond my Calc 101 education lol. I did however find this quote online: "According to a book title "Legends and Reality of the AK" the testing of the prototypes at that took place at the Izhevsk factory, that during the durability test each prototype had ran through more the 13,000 rounds before testing was terminated because all on hand ammunition had been fired."

 

Quite an impressive statement. I just wonder how long it took to go through that many rounds.

 

thats interesting, although im guessing they were testing to see if they could push the rifle so hard it couldnt fire rounds anymore. i dont see how you could fire off that many rounds through one rifle in rapid succession and not damage the rifling in the barrel.

[cormyr 0]

Hmm. Sounds like the math involved in that equation goes a bit beyond my Calc 101 education lol. I did however find this quote online: "According to a book title "Legends and Reality of the AK" the testing of the prototypes at that took place at the Izhevsk factory, that during the durability test each prototype had ran through more the 13,000 rounds before testing was terminated because all on hand ammunition had been fired."

 

Quite an impressive statement. I just wonder how long it took to go through that many rounds.

 

thats interesting, although im guessing they were testing to see if they could push the rifle so hard it couldnt fire rounds anymore. i dont see how you could fire off that many rounds through one rifle in rapid succession and not damage the rifling in the barrel.

 

 

from all the research i've done regarding this issue, i have not seen ONE mention of an ak47 barrell overheating to the point of self-destruct. maybe it is true. perhaps they are indestructable...

[XdamagedX 248]

from all the research i've done regarding this issue, i have not seen ONE mention of an ak47 barrell overheating to the point of self-destruct. maybe it is true. perhaps they are indestructable...

maybe cadillac should make bumpers out of them then lololol

[Saiga_rom 91]

Hmm. Sounds like the math involved in that equation goes a bit beyond my Calc 101 education lol. I did however find this quote online: "According to a book title "Legends and Reality of the AK" the testing of the prototypes at that took place at the Izhevsk factory, that during the durability test each prototype had ran through more the 13,000 rounds before testing was terminated because all on hand ammunition had been fired."

 

Quite an impressive statement. I just wonder how long it took to go through that many rounds.

 

thats interesting, although im guessing they were testing to see if they could push the rifle so hard it couldnt fire rounds anymore. i dont see how you could fire off that many rounds through one rifle in rapid succession and not damage the rifling in the barrel.

 

 

from all the research i've done regarding this issue, i have not seen ONE mention of an ak47 barrell overheating to the point of self-destruct. maybe it is true. perhaps they are indestructable...

 

theres a difference between self destruct and compromised accuracy. AKs are tough as hell, but the materials they are made out of can still be damaged if you abuse them. note the difference between "damaged" and "completely destroyed"

[Saiga_rom 91]

from all the research i've done regarding this issue, i have not seen ONE mention of an ak47 barrell overheating to the point of self-destruct. maybe it is true. perhaps they are indestructable...

maybe cadillac should make bumpers out of them then lololol

 

made with genuine, 100% AK parts!!

 

lol

 

id buy one!!!

[Saiga_rom 91]

yea, its true that each firearm will heat up at a different rate. i saw on sons of guns last night that when an M16 fires 300 rounds in full auto, the barrel becomes red hot. like literally, the same color as an electric barbecue starter. it cant be good for a rifle to be heated to this point, and then rounds continue to be fired through it. materials becomes soft when they are extremely hot

[bpipe95 8]

yea, its true that each firearm will heat up at a different rate. i saw on sons of guns last night that when an M16 fires 300 rounds in full auto, the barrel becomes red hot. like literally, the same color as an electric barbecue starter. it cant be good for a rifle to be heated to this point, and then rounds continue to be fired through it. materials becomes soft when they are extremely hot

 

The gas tube got red hot not the barrel. Any "light duty gun" running full auto running for that many rounds will get hot, see AK burning furniture vids.

 

On an AR the gas tube will usually fail first, if they had kept going it would sag then burst.

 

You can burn out a barrel with temps and cause perm damage, but it will not usually burst unless the barrel sags and causes rounds to not be expelled. Once that happens the BOOM is next in line.

Edited March 25, 2011 by bpipe95

[Saiga_rom 91]

yea, its true that each firearm will heat up at a different rate. i saw on sons of guns last night that when an M16 fires 300 rounds in full auto, the barrel becomes red hot. like literally, the same color as an electric barbecue starter. it cant be good for a rifle to be heated to this point, and then rounds continue to be fired through it. materials becomes soft when they are extremely hot

 

The gas tube got red hot not the barrel. Any "light duty gun" running full auto running for that many rounds will get hot, see AK burning furniture vids.

 

On an AR the gas tube will usually fail first, if they had kept going it would sag then burst.

 

You can burn out a barrel with temps and cause perm damage, but it will not usually burst unless the barrel sags and causes rounds to not be expelled. Once that happens the BOOM is next in line.

 

ahh yes, you're right, it was the gas tube which was glowing red.

[MT Predator 2,294]

If you get it hot enough your rounds will cook off in the chamber and fire as well causing a runaway gun.

[Saiga_rom 91]

If you get it hot enough your rounds will cook off in the chamber and fire as well causing a runaway gun.

 

heh, poor man's full auto eh?

 

lol

[MT Predator 2,294]

If you get it hot enough your rounds will cook off in the chamber and fire as well causing a runaway gun.

 

heh, poor man's full auto eh?

 

lol

Yeah and you'd be that much poorer permanently damaging your barrel. That's why MGs have quick change barrels and a manual of arms requiring the gunner to change barrels dependent on how many rounds are fired.

[Scott Kenny 144]

To cause damage? about 300 rounds worth of continuous mag-dumps, maybe less. An M16 will get hot enough to cook rounds off after about 160 rounds, but you haven't hurt the gun... yet.

 

To stop the gun from firing? You don't have enough ammo, nor enough people to reload the empty magazines. Seriously. M60s (not the most reliable gun in the world) can shoot until the barrel is glowing red-hot and keep going. That barrel is scrap after the event, but they'll keep shooting.

[SOPMOD 254]

Longest continuous string of rapid semi auto fire I ever did was trying to cook a Vortex Strikefire dot sight on an Ultimak rail. A total of 380rds and there were no ill effects other than being too hot to hold and killing the red dot sight. Longest string of full auto was at a machinegun shoot where I fired 180rds while teaching a buddy how to lean into the weapon and do quick mag changes and that same AK was rented and shot for the whole weekend afterwards.

 

This guy shoots drum after drum full auto and the weapon was not destroyed.

 

http://www.youtube.com/watch?v=xe2jUEaTBVA