How HOT does an AR15 Barrel get in Sustained Fire?

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[ARCHIVED THREAD] - How HOT does an AR15 Barrel get in Sustained Fire?

Posted: 1/7/2002 11:13:31 PM EDT

I would like to know what temperature can a barrel reach after sustained firing, ie. 30rd, 60rd, 90rd? Would it exceed 600F?

The reason I'm asking is I plan to install a muzzle brake on the barrel using JB Weld. I've successfully done that with a setscrew brake on my AK.

While there's no setscrew AR brake, as long as the barrel and muzzle stay below 600F (the operational limit of JB Weld), the brake should hold, theoretically. The brake I have in mind is the Cav-Comp post-ban bird-cage. There's also a roll pin installed with the comp, I hope it'd help holding it together.
http://www.brownells.com/images/products/100000189.jpg

Anyhow, if you have knowledge or any experience or info in what I'm planning to do, please post. Thanks.

Posted: 1/7/2002 11:56:12 PM EDT

[#1]

It gets hot enought to melt the paint on a Honda Civic, trust me I know.

Posted: 1/8/2002 5:03:05 AM EDT

[#2]

From what I understand, if the bbl. is threaded the brake must be (at least) silver soldered in place.

Posted: 1/8/2002 10:20:34 AM EDT

[#3]

yeah, but I don't plan on threading the barrel. JB Weld and the roll pin alone should hold the brake on, as long as the temp doesnt' exceed 600 F.

Posted: 1/8/2002 10:27:28 AM EDT

[#4]

I don't think that 90rds with get your barrel into the 600 range. Though I have seen an M16 barrel red hot but that was after maybe 500 rounds of full auto fire.

Posted: 1/8/2002 10:35:19 AM EDT

[#5]

I wouldn't rely on JB weld in HIGH heat. I fixed a friend's bread maker with JB Weld, and the stuff MELTED under the heat. It's good for filling holes and has some fixative properties, but my guess is you'd be sending that comp down range in a hurry.

Posted: 1/8/2002 10:57:03 AM EDT

[#6]

Quoted:
I wouldn't rely on JB weld in HIGH heat. I fixed a friend's bread maker with JB Weld, and the stuff MELTED under the heat. It's good for filling holes and has some fixative properties, but my guess is you'd be sending that comp down range in a hurry.

How "HIGH HEAT" is high heat? Bread makers can get pretty hot.

Posted: 1/8/2002 11:05:25 AM EDT

[#7]

The new SOCOM III carbine specify a heat resistance of 1,000 degrees; the current M-4 barrels cannot take this abuse, and the Army is looking at alternatives from Industry: thicker barrels (with no M-203 cut-outs), coatings, fluting, etc.

Posted: 1/8/2002 11:53:03 AM EDT

[#8]

Quoted:
Quoted:
I wouldn't rely on JB weld in HIGH heat. I fixed a friend's bread maker with JB Weld, and the stuff MELTED under the heat. It's good for filling holes and has some fixative properties, but my guess is you'd be sending that comp down range in a hurry.

How "HIGH HEAT" is high heat? Bread makers can get pretty hot.

Bread makers probably don't hit 600 Degrees..... your standard kitchen oven maxes out at 500 degrees.

Posted: 1/8/2002 12:11:51 PM EDT

[#9]

Originally Posted By Beyond_Visual_Range
How "HIGH HEAT" is high heat? Bread makers can get pretty hot.

I'd be surprised if Bread Makers get much beyond 375 deg F. Beyond that you'll burn the bread and not bake it.

Posted: 1/8/2002 12:39:23 PM EDT

[#10]

I have an AK74 brake on a 5.45x39 rifle that I used JB Weld on and even after some fast shooting it did not loosen up at all. I know you said it wasn't going to be threaded, but for those that repeat what the ATF claims about how it must be silver soldered, on fuck that. If a pinned and silver solderd brake can be removed and swaped out by any gunsmith in minutes nothing is permenant, so why worry about it. There's no way I can get it off and the law say's permenant not silver solderd.

Posted: 1/8/2002 4:57:31 PM EDT

[#11]

375F, that's what I thought the bread maker tops at. The instruction for JB Weld says it's stable up to 600F, which I hope it's true. There's also a quicker version of JB Weld that melts at 300F. That maybe what you were using.

Posted: 1/8/2002 5:21:32 PM EDT

[#12]

From what I understand, if the bbl. is threaded the brake must be (at least) silver soldered in place.

This is to satisy ATF regs for post ban assault rifles - it's what the ATF considers "permanently attached". However, silver solder and a MAPP torch seems like a better solution than what you propose. This would raise your heat limit to 1100 degrees.

Posted: 1/8/2002 7:08:16 PM EDT

[#13]

This is to satisy ATF regs for post ban assault rifles - it's what the ATF considers "permanently attached". However, silver solder and a MAPP torch seems like a better solution than what you propose. This would raise your heat limit to 1100 degrees.

I didn't want to heat the barrel to 1100 along with the brake. If there's no metal hardening, there'd be at least color discoloration to deal with. That's not gonna be good for a new Bush XM15.

Posted: 1/8/2002 8:10:47 PM EDT

[#14]

Why not press the brake on ?

I've made several "homemade" brakes for myself and a few buddies, and the best way as far as I'm concerned, is to press it on with a hydraulic shop press...
No heat, no mess, more secure fit...

I've made them for AK's and AR's...

Only takes about a .0015-.002" press fit...
Better get it aligned right the first try too, you don't get a second chance...
I tried removing one of them later on, and WISHED I had a loose silver soldered brake...
I had to cut it off...

Just my 2 cents...

Posted: 1/8/2002 8:52:11 PM EDT

[#15]

who would have such a press? any commercial brakes that were designed to be installed using a press? Does this affect the barrel at all? I can imagine what you mean by Better get it aligned right the first try too, you don't get a second chance...

[ARCHIVED THREAD] - How HOT does an AR15 Barrel get in Sustained Fire?

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