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1/25/2018 7:38:29 AM
Posted: 6/25/2002 7:22:49 PM EST
Went to the range the other day and had a good time with my Beta mag, the only problem was that it worked too good and looked down to see my barrel smoking about the same time that someone told me I should slow down a bit because I would get the barrel too hot.
I see you can buy a infrared thermometer gun now for about $70 and thought it would be interesting to measure the temp of the barrel next trip to the range.
So my question is: How hot is TOO hot?
Can someone give me an answer in degrees?
Link Posted: 6/25/2002 7:25:05 PM EST
I don't know for sure but I am willing to bet that if it is smoking, it's too hot

Link Posted: 6/25/2002 7:28:20 PM EST
I worry about getting the barrel too hot also. My Bushy HBAR doesn't heat up that quick and seems to cool down fast. On the other hand, my RRA M4 gets very hot quickly and seems to never cool down. I had heard the opposite regarding this, but thats not whats happening.

Link Posted: 6/25/2002 8:05:50 PM EST
You didn't say if you were shooting semi or full-auto. I called Bushmaster a few years back, and I spoke with Tom Barr, and he says "you can't pull the trigger fast enough to overheat one of our barrels in shooting semi-auto."
Link Posted: 6/26/2002 3:00:45 AM EST
If your handguards aren't melting, your barrel isn't too hot

Link Posted: 6/26/2002 3:34:18 AM EST
Worloard, I recall when you posted that ,/, I would not say he needs a new barrel though, if you sell it i believe you should tell the prospective buyer how many times it was heated up like that though, May never see them again , would not like to find out though.
Being straight is being straight.
O-Ya , iam interested in that temp. gun thing , let us know how it works out, accuracy and as such.
Link Posted: 6/26/2002 3:43:05 AM EST

How hot is TOO hot?

when it starts to droop
Link Posted: 6/26/2002 6:09:50 AM EST
From what I understand (I'm not a metallurgist) is that you never want to exceed the draw temperature of the steel used to make the barrel (for too long without a good cause). Normally this is over a thousand degrees, which can be reached with just a few hundred rounds shot in a minute.

Once I saw a guy empty a 100 round beta mag in less than a minute, which ended up melting his handguards.

I've run 140 rounds of .308 though an FAL as fast as possible and ended up heating the steel handguards to the point that I had to use the bipod legs to hold the rifle. I set the thing down and the rain falling on it steamed up half the clearing I was shooting it.

When you measure the temperature be sure to share it with us and take several measurements along the length of the barrel. Wear gloves!
Link Posted: 6/26/2002 6:36:38 AM EST
I have heard that the gas tube will melt before the barrel gets damaged from the heat.

The gas tube acts like a fuse. It is the weaker link in the system, and when it blows, it is time to slow down.

I don't know if this is absolutely true or not, but it makes a lot of sense.
Link Posted: 6/26/2002 6:46:58 AM EST
High temps do accelerate throat erosion. A couple years ago I went to Knob Creek. This guy had a 1919 shooting 8mm (Hi Dave). I never once saw him stop firing that the gun wasn't jammed or the belt empty. I asked my buddy - "Doesn't that eat the heck out of the throats?" to which he replied "I don't think he cares." Later the guy said he had like 1 ft of rifling left in the barrel.

That's not the only way you can damage the barrel though. I was blazing away with my semi AR. Boiled off the oil in the parkerizing. Put it in the case, got home two days later and my barrel had a light coat of ORANGE RUST. Burned off the oils and water was able to get to it. Rode hard and put up wet.
Link Posted: 6/26/2002 6:52:59 AM EST

Originally Posted By bill3508:
I worry about getting the barrel too hot also. My Bushy HBAR doesn't heat up that quick and seems to cool down fast. On the other hand, my RRA M4 gets very hot quickly and seems to never cool down. I had heard the opposite regarding this, but thats not whats happening.


Sorry, Bill, it doesn't work that way. If something takes a long time to heat up, it takes a long time to cool off. Conversely, if something heats up quickly, it cools off quickly.
Link Posted: 6/26/2002 7:06:49 AM EST
LarryG, I think you are assuming that "all things are equal". If the M4 barrel has those double shielded handguards they will keep the user from feeling the heat, but the barrel will stay warm longer due to the restricted airflow. If you actaully check the barrel heat, you will probably realize it is taking a while to cool.

The HBAR probably feels hotter, even at a lower barrel temp than the M4. Espicially if it has sometype of ventilate hanguard system RAS/RIS/SIR/SKIP/BOB whatever. But most after market guards will allow more airflow and quicker cooling. A1 guards will also allow more air than the M4's, I'm not sure about A2 guards but expect they are similar to A1's.

Sustained rate of fire for an M-16A1 is 12-15 per minute. Rapid fire is something like 20 per minute for 10 minutes.

I suspect that if you melt your gas tube you have already damaged the barrel. The heat treatment has been "weakened" and wear will accelerate.

I would guess the same for "melted handguards".

Smoke coming off isn't neccesarily bad. It could be that light coat of "surface oil" leaving the building. But that probably is a warning sign.

When you want to cool the barrel don't underestimate how much heat can be dissipated through an open bolt.
Link Posted: 6/26/2002 7:12:02 AM EST
i have heard of a guy shooting a beta C out of a pistol leanth (i think) upper m16. if i remember correctally, his buffer tube (WOW) melted.
Link Posted: 6/26/2002 7:14:07 AM EST
As I said its not supossed to work that way. But my M4 get hotter quicker and does not cool down fast compared to my Bushy 20" Hbar. This is not using scientific means, just waiting until the barrel won't burn my hand. If its the M4 handguards doing it I may try something else as I would rather have it cool down faster.

Link Posted: 6/26/2002 7:17:41 AM EST
In the Army my dad said they shot their M14's until the barrel's would glow in the dark..

Link Posted: 6/26/2002 11:21:56 AM EST
You can always buy a new barrel

If the '94 ban sunsets you can always change out the postbans to have bayo lug and FS in this manner...
Link Posted: 6/26/2002 11:31:32 AM EST
[Last Edit: 6/26/2002 11:37:30 AM EST by poikilotrm]

Originally Posted By OLY-M4gery:
Sustained rate of fire for an M-16A1 is 12-15 per minute. Rapid fire is something like 20 per minute for 10 minutes.

Oly I thought you were full of poop as we would quite regularly exceed 12-15 rounds per minute in the service and I regulary do 30 second drill with a 30 round mag with no apparent ill effect to my weapon. But...

Go to Enter, then police trainer's archives, then firearms safety, the M16 ammunition cookoffs.

Man! I thought 12-15 rounds per minute was for artillery only. I stand corrected. Not that that changes anything for me in a real world sense.
Link Posted: 6/26/2002 12:59:22 PM EST
Last shoot, one guy put about 15 twenty round mags through his G3 in about 3 minutes. It was white hot, literally. This was full auto btw. I've also seen about 400 rounds through an M16 in about 5 minutes or so. The rifle was hot for awhile, but cooled off eventually.
Link Posted: 6/26/2002 9:14:42 PM EST
I put 100rds of wolf through my SKS. While reloading the barrel touched my neck. Instant second degree burn. My colt HBAR is only pleastly warm after 100 rds. At about 150 (in 10 minutes)its not fun to touch.
Link Posted: 6/27/2002 5:07:40 AM EST
[Last Edit: 6/27/2002 5:08:51 AM EST by Redmanfms]

Originally Posted By 7:
Last shoot, one guy put about 15 twenty round mags through his G3 in about 3 minutes. It was white hot, literally. This was full auto btw. I've also seen about 400 rounds through an M16 in about 5 minutes or so. The rifle was hot for awhile, but cooled off eventually.

Yeah. I remember that. It cooked the finish right off the barrel.

He also cooked his suppressor onto your M4 with like 10 mags in 2 minutes.

Somebody above stated that they saw a fellow melt his gas tube with a Beta-C dump. The guy wasn't shooting off a cool (or even warm) weapon if that happened. As 7 can attest, there were a number of guys from subguns doing drum dumps, including a couple Beta-Cs through M4s, nothing overly damaged other than finishes.
Link Posted: 6/27/2002 7:51:02 PM EST
If you want to overheat your barrel, good luck, youll never do it. A Beta C? your finger must have been cramping big time
Link Posted: 6/27/2002 8:28:01 PM EST
when it gets hot, dont touch it! i did once. not on purpose though!
Link Posted: 6/27/2002 8:59:36 PM EST
I had just dumped over 100 rounds within 5 minute session. One of my friends accidentally hit his inner forearm closer to the muzzle end.
His "tat" of a mini-y and end of barrel just fully healed few months after the fact.

All I could is laugh, cool friend aren't I?
Link Posted: 6/27/2002 9:09:22 PM EST
When It Melts!
Link Posted: 6/28/2002 3:17:37 AM EST
According to Colt, 12-15 rpm will go indefinately without overheating.

140 rounds in one minute gets you into the "cook-off" danger zone.

Repeated full-auto past the safety zone can bring the barrel temp to 1360 degrees. At that point, the bullet can exit through the handguards which generall ruins weapon and day alike.

It was explained to me that this has only really been documented in the military with units such as the SEALS who tend to train / use their M-4s in a role more closely designed for an SAW.

Though you are not likely to get to the terminal failure point on semi, 140 rpm is easily attainable in semi. And, as stated before, repeated heating in this fashion will accellerate barrel wear / throat erosion.

Link Posted: 6/28/2002 7:04:05 AM EST
Someone from bushmaster posted on this board some time back that you can't get your barrel hot enough to melt it, and there is nothing that you can to do your barrel with a semi AR...

Link Posted: 6/28/2002 7:12:11 AM EST
I had an AK that I burned the finish off the barrel. It started to rust after that. Luckily it was an AK, so I didn't worry about damage to accuracy.

Has anyone had a round cook off? I haven't so far.
Link Posted: 6/28/2002 7:33:22 AM EST

I have never seen it happen, and I simply can't imagine the volume of fire it would take to turn the metal to a liquid state. Then again, who knows what sort of operating conditions some of our Nation's finest subject these weapons to.

The Colt instructor who relayed this information to us in class merely stated it to follow up to the cook-off limit question that a student posed. He insisted that it was purely due to the weapon being used well beyond it's designed capacity for an extended time, and that it was a testament to the reliability of the system overall. Come to think of it, if the system continues to chug along until the heat of the barrel causes it to be unable to contain the projectile or gases, that's one hell of a system.

He also claimed that since these teams are resistant to going to a more appropriate weapon platform for a SAW role, various experiments with heavier barrels and fluting are being conducted to help extend the operating levels.

Of coarse, he could have been full of BS, but his credentials were much higher than my own, and he has been in a position to inspect and repair such weapons.

Damn, that would HAVE to take ALOT of ammo. Probably more than I could carry comforatably.

Link Posted: 6/28/2002 9:32:14 AM EST
[Last Edit: 6/28/2002 9:39:33 AM EST by WhiskeyBravo]
Armalite has in one of their tech notes that the composition of an M4 barrel changes dramatically after reaching 1100 degrees or more & that this may cause it to fail at a later date. They said that failure is not guaranteed but that the change in composition is and is irreversible. Not sure if this is true or not but it pains me to think that at the very least my barrels accuracy may be affected and I would not know the reason why.

Link Posted: 6/28/2002 9:53:27 AM EST
My dad told back in his army days he was down in fort hood shooting fiftys with a couple of ops boys. They shoot so much off the barrel turn red in the darkness. I dont know if he was joking or not.
Link Posted: 6/28/2002 10:27:54 AM EST
If you're in a situation where you REALLY NEED TO fire your weapon to the degree that it may be damaging to the barrel, the least of your concerns will be damaging your barrel.
Link Posted: 6/28/2002 12:52:04 PM EST
I've read stories of SEALs actually melting their barrels and in other instances getting them so hot that they could actually see the darkened shape of the projectiles moving through the barrel.

I don't know about non-precision firearms but I once red that you should keep precision barrels under 150 degrees Farenheit.
Link Posted: 6/29/2002 8:31:55 PM EST
I was feeling stupid with a couple of my friends when we where on my buddys property. We dumped so much ammo through my bushmaster in such a short period of time you could only touch the pistol grip and butt stock. I am not kidding. you could not touch the handguards. I would not make a habit of this, but it still shoots fine.
Link Posted: 6/30/2002 9:57:01 AM EST
I have had a good number of guns built for benchrest with the best barrels available. Always I asked the smith building what is too hot, and far ahead of other answers was that if you can't put your hand on it and leave it there then it's too hot!!! Obviously different calibers and diferent guns will heat and cool at different rates, so this is rule of thumb. This was brought home convincingly to me by pictures through a bore scope of before and after of a quality barrel. As I understand it all barrels will develope cracks internally but heating and cooling excessively cause more severe cracks. I posed this question also because I had heard that some varmint shooters were using a number of methods to quick cool barrels, namely CO2. I could not believe that this would only wreek havoc on the molecular structure of a barrel. Several gunsmiths agreed. Now if you are rich and consider good barrels a dime a dozen then this is a mute point but I myself buy/build thr best I can afford and take care so that it will last as long as possible. And as far as that goes when I was in the service I did not see any body ,Self included that worried about what was happening to the barrels when we smoked them as long as they shot. We didn't have to pay for them. So now when I'm paying I keep in touch with my barrels Not that in competion They don't get them hot but that I use he touch methoud when not pressed. IMHO
Link Posted: 6/30/2002 7:21:20 PM EST
I had a upper that had a barrel that was pretty well shot, decided to see how much it could take. Went to the range with thirty 30 round mags and a beta-c drum filled to the max. I would load and shoot the mags as fast as i could. I emptied all the mags and got to the drum thats when things started going wrong. The handguards melted off in my hand and you could actually see the shadow of the bullet going down the barrel. Now that was hot.
Link Posted: 7/1/2002 10:14:44 PM EST
Thanks to everyone who responded!
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