How hot can i get my barrel

[rallyhound]

I was wonder how hot i can allow my barrel on my AR or AK to get before i risk causing damage.
During rapid fire fun it sometimes gets way to hot to touch.
I have one of those infrared thermometers, is their some magic number?

 

[JohnKSa]

What kind of damage are you worried about?

It's not like you're going to lose the precision accuracy you're currently enjoying. And the barrel isn't likely to come apart on you. I wouldn't worry. It's an AK!

 

[f4t9r]

I have wondered that myself I always try to be careful and shoot in burst when just letting them fly , you are right it does not take much to get barrel hot to the touch.
Im sure someone will know !!!!!

 

[Bartholomew Roberts]

Here is one magic number for you 600F - that is about the chamber temperature where you will begin to see cook-offs because the chamber is hot enough to detonate the primer. You can have cook-offs at much lower temperatures than that, particularly if the ammo has been stored badly and the primers have become unstable; so don't think you are safe just because you are at 550F.

On ARs, I wouldn't sweat it too much. You can hit barrel temps of 300F pretty regularly and your standard chrome-lined barrel will still be good for hitting silhouettes out to 600yds for about 10k rounds. You may start losing consistency at longer ranges around 5k though.

On AKs, I wouldn't sweat it either as there isn't a whole lot of precision to use.

With standard handguards on either rifle, a good rule of thumb is to stop shooting and let it cool when you see smoke coming off the handguards (you can ignore white smoke from AR handguards, that is just CLP burning off - black smoke is the glue holding the metal heat shields burning and that is a good sign to stop).

If you want the absolute maximum possible life out of your barrel, just stop shooting whenever the barrel gets too hot to hold with your bare hand; but you can exceed that standard quite a bit and get and still get 10-20k rounds of use out of a barrel.

 

[Sunray]

Sometimes??? It'll always get too hot to touch shooting rapidly. We used to be able to get the wooden forestock an a C1A1 smoldering with two 20 round mags. Some of them were charred from it. Never bothered the rifle though.

 

[Dave R]

My personal rule is, if you're uncomfortable (with the temp,) the gun is uncomfortable, too.

That gives a pretty wide safety margin.

 

[Highland Ranger]

Hot to the touch is around 115 degrees F which is nothing for steel.

Two issues that I can think of (putting on my engineer hat):

1. Permanent Distortion of the barrel from excessive heat - I think this falls under the category of "good luck". Steel starts moving around up in the 600, 700, 800 degree range - don't remember my metallurgy but I am think it'd be real hard for you to heat it up enough to distort the barrel. At that temp, you'd have trouble holding it. Depends on the composition of the steel as well as the dimensions of the part.

2. Mechanical damage from shifting tolerances and or localized spot heat: you could get increased barrel wear or wear on other parts if things expanded from the heat . . . . again not sure this would be an issue.

Can't think of anything else . . . . but in both cases I'm thinking it'd be hard to hurt a semi auto from heat.

 

[Bwana John]

Heat AND pressure both cause erosion.

I remember reading somewhere an ordinance test that burned up a machine gun barrel in 3000 rounds of constant firing (about 5 minutes).
They just kept slapping on new barrels and kept firing for quite a few more barrels before any other parts failed.

 

[Bartholomew Roberts]

For another good reference point, dumping a mag from an M4 barrel as fast as you can will take you from a cold start of 86F to 230F.

 

[Keaner]

I was actually wondering about this with my M1. It gets rediculously hot (even the front handguard, and upper handguard), so that it causes plastic bags to melt immediately on contact. And this is only about 100 rounds worth!

The only damage I could think of would be for the barrel to sag.

 

[NMshooter]

You would be very hard pressed to fire a semi-auto rifle fast enough to heat up the barrel until it glowed.

Long before that you will set wood handguards on fire, and run the risk of melting plastic handguards, both depending on any heatshields the rifle may have.

Not something to worry about unless you have a selective fire weapon.

 

[Peter M. Eick]

I have fired my M1A's fast enough to get the oil on the barrel to smoke a bit, but I really doubt I got it that hot to do much damage to the gun. My personal bet is still that you do far more damage by cleaning then by shooting unless you have a full auto (idiots and damage done by stupidity are excluded).

 

[1911user]

So the AR15.com reliability test (6 mags fired quickly) isn't too hard on the AR?

 

[Bartholomew Roberts]

So the AR15.com reliability test (6 mags fired quickly) isn't too hard on the AR?

That will probably put the temperature up around 500F if you use an M4 barrel and the ambient temp is around 85F. If you do that kind of thing consistently, it will decrease the lifespan of the barrel. How much it will decrease the lifespan depends on what accuracy standard you need at and what ranges you plan to shoot it.

If a military acceptable 4MOA is good enough for you and you never shoot past 100yds, then you can do 6-mag dump tests like that for tens of thousands of rounds before you'll notice anything.

On the other hand, if you want to hit highpower targets at 600yds, you'll might notice issues as early as 3k rounds with an M4 barrel if you do a lot of the above kind of shooting.

Think of it kind of like gas mileage... you can get better mileage by driving everywhere at 25mph; but while you'll use more gas going 70mph, you will still run out of gas either way. It is just a question of whether you make it 250mi. or 300mi.