How hot is too hot? Suppressor+AR style 308

[SamT1]

So how hot are you willing to get your barrel? I shot a full 25rnd P mag today of 308 win through the AR 308 at a pretty rapid pace.

Today I was doing a little hog sniping practice. I’ve always been weak at trying to take out a large group so I setup my 8” gong at 400. Dialed to 400 (7moa) on my setup. And proceeded to dump a 25 round P mag as fast as I could stay on target. I need to add some other targets so I’ll move around more, but that’s for another day.
It was sprinkling and when done it was picking up. The rain drops were boiling off as soon as they hit the gun. Accuracy never fell off. I was hitting more towards the end of the string than at first probably due to nerves. (Counted at least 15 hits on a fresh painted gong, but maybe a couple more that stacked) so I ran 25 rounds in probably 1 minute. Got the thing pretty dang hot. Am I risking cooking anything or doing permanent damage? When do you back off?

 

[wally]

I don't think 25 rounds per minute will be a problem until the gun gets too dirty to function. With an AK you don't have to worry until after the handguard catches fire

With sustained full auto the gas tube on the M4 is usually what fails first, effectively turning it into a straight pull bolt action with poor ergonomics


probably would have happened sooner with faster mag changes and the plastic handguard did start burning just like the AK

On this one with an aluminum handguard you can see the gas tube glow.


Considering it was a commercial upper I was pretty impressed, although the barrel failed before the gas tube on this one.


For reference a full auto AK fired to stoppage:


I love the field expedient "gunsmithing" to get it back in action at about 17 minutes in

 

[Varminterror]

Barrels are consumable. Cores are consumable - and for some companies, are warranty replaced.

I shoot as fast as my application demands, and my rifle gets as hot as such speed results. Sometimes that is hot enough to burn skin, sometimes the barrel doesn’t even get above “cool.”

 

[Robert]

I used my FAL in a competition back when it still had stock handguards. The handguards started to warp and you couldn't touch them after one long stage. I switched to the DSA "float" tube and it made a ton of difference.

 

[Jackal]

You really cant get it hot enough to damage it, without doing many multiple mag dumps.

 

[SamT1]

Thanks guys. This thing is super accurate and I’d hate to damage that. I’ve got lucky with a cheap barrel and doubt I could do it again so I’d have to buy a good barrel and really need to spend that money on a range finder.

 

[Jim Watson]

Mr Browning fired a 46 minute demonstration, 26000 rounds or thereabouts. The Army didn't believe his 20000 round demonstration.
Of course HIS guns were water cooled.

 

[SamT1]

Yea and I need to keep shooting well under MOA until the barrel wears out naturally.

 

[marksman13]

You didn't hurt it at all. You'd be hard pressed to hurt your barrel or suppressor in semi-auto without intentionally trying to hurt them. You may shorten your barrel life a little in terms of throats erosion, but even that would almost have to be intentional unless you were at a carbine class with multiple rapid fire engagements.

 

[MachIVshooter]

Mr Browning fired a 46 minute demonstration, 26000 rounds or thereabouts. The Army didn't believe his 20000 round demonstration.
Of course HIS guns were water cooled.

Yeah, once the equilibrium is reached, it doesn't really matter if it's 200 rounds or 20,000. Not unlike an automobile engine, where no coolant = death in minutes, but proper cooling and lubrication allows the things to run for thousands of hours.

 

[FL-NC]

A suppressed military M4 will reach cook-off temps at an ambient air temp of 70 degrees fahrenheit after 90 rounds cyclic full auto.

 

[IndianaBoy]

Continuing to shoot while your barrel is hot will shorten barrel life. Just the nature of the beast.

That being said, these guns we buy are made to be shot. You will get many thousands of rounds out of a typical semi-auto before the barrel is toast. But really, it depends on your accuracy requirement.

Most of us can expect to get from 5-15,000 rounds before accuracy will fall off to the point that we notice it. Barrels are dirt cheap compared to the cost of the ammo it takes to wear one out. You won't hurt anything unless you load up 10x magazines and proceed to dump them through the gun in an effort to burn the thing out.


I am comfortable getting my barrels hot. I have, like you mentioned, had rain drops boiling off of my silencer as soon as they hit it. I have fired nearly 60 rounds in under a minute on a 3-gun course of fire. I scoped my 3 gun barrel the other day and there is a lot of flame cracking, but it still shoots well. The replacement is already propped up in the corner of the safe but I'm not gonna swap it out until the old one won't group well anymore.

 

[Klint Beastwood]

So how hot are you willing to get your barrel? I shot a full 25rnd P mag today of 308 win through the AR 308 at a pretty rapid pace.

Today I was doing a little hog sniping practice. I’ve always been weak at trying to take out a large group so I setup my 8” gong at 400. Dialed to 400 (7moa) on my setup. And proceeded to dump a 25 round P mag as fast as I could stay on target. I need to add some other targets so I’ll move around more, but that’s for another day.
It was sprinkling and when done it was picking up. The rain drops were boiling off as soon as they hit the gun. Accuracy never fell off. I was hitting more towards the end of the string than at first probably due to nerves. (Counted at least 15 hits on a fresh painted gong, but maybe a couple more that stacked) so I ran 25 rounds in probably 1 minute. Got the thing pretty dang hot. Am I risking cooking anything or doing permanent damage? When do you back off?

But to answer when enough is enough, usually I call anything gun related quits when you START to see the red glow from the heat. Wear an oven mit. Especially doing a spare barrel change on a crew serve...made that mistake before. Paid for it for about two weeks.

 

[SamT1]

Thanks for the replies guys. I doubt I ever rapid fire more than one mag.
I’ve went through 60 before hunting pigs, but the population is not near what it was at that time.