REMOVE A BRAZED IN FLASH HIDER

109Hammer said:

Will a propane torch with map gas heat it enough so i can tap it out, or can that damage the barrel?

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MAPP gas gets ~3670F out of a propane torch, held on a barrel long enough it would certainly cause damage. That said, any solder or braze there would have required heat in order for it to be there.

Both are methods worth learning how to do but I wouldn't suggest one learn on anything important.

Although acetylene has a higher flame temperature (3160 °C, 5720 °F), MAPP has the advantage that it requires neither dilution nor special container fillers during transport, allowing a greater volume of fuel gas to be transported at the same given weight, and it is much safer in use.

MAPP gas has not been mfg. in North American since 2008

MAPP gas was a trademarked name, belonging to The Linde Group, a division of the former global chemical giant Union Carbide, for a fuel gas based on a stabilized mixture of methylacetylene (propyne), propadiene and propane. The name comes from the original chemical composition, MethylAcetylene (48%) -Propadiene (23%) -Propane (27%).

MAPP is NOT Mapp Pro.

What is available is Mapp Pro= 0.5 % propaPe + 99.5 % propylene

Mapp Pro has propylene added that allows the gasses to transfer heat into the material faster, not hotter.

However, the original MAPP mfg. still use the same familiar yellow bottles for MAPP-Pro …..who knew.

Mapp gas may not do the job fast enough.
A key to this sort of job is heating the parts FAST to limit heat spread. For that you need acetylene.
The longer it takes to heat, the more it spreads, and more risk of damage.

If the actual pin is brazed in, you'd probably need to drill or grind the brazing out to extract the pin.
Pin jobs usually welded over the pin not brazed it.
It may be possible to extract the pin without any heat by grinding or drilling.

Before going too far I suggest looking things over very carefully so you can be certain exactly what you have.
Is just the pin bonded, or is the entire muzzle attachment brazed?
If you get the braze out of the way, how can you extract the pin? Usually pins were blind installed, not drilled all the way through.

What’s going to happen when you get the flash hider off? Will you instantly have an illegal SBR? Most pinned flash hiders are extending short barrels.
I will agree with the comments on using Oxy-Acetylene. Need to heat up fast to minimize heat damage, probably should use heat block paste also.

a5werkes said:

Although acetylene has a higher flame temperature (3160 °C, 5720 °F),

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Thats with oxygen not just acetylene.

It makes a difference, MAPP in oxygen moves up to 5300F, for example.

Propane alone is just shy of 3600 F and over 5000 F as well, with oxygen.

Need to heat it faster with an oxy+fuel torch using a rose bud.

Kp321 said:

What’s going to happen when you get the flash hider off? Will you instantly have an illegal SBR? Most pinned flash hiders are extending short barrels.
I will agree with the comments on using Oxy-Acetylene. Need to heat up fast to minimize heat damage, probably should use heat block paste also.

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No need to speculate. I just assume it's a 16+ inch colt "not an assault weapon upper" from the late 80s to 04. From when colt though they could appease gun grabbers through the assault weapons ban.

Oh then take it off with a grinder.

Unless your'e trying to save the flash hider, the simplest and safest method is to saw and grind the thing off.
Heating gun barrels may not necessarily be bad for them, but it ain't good either. Anytime you can prevent that, you're not risking a barrel.

109Hammer said:

No, it's not an SBR. The rifle was originally sold in CT where it was required that a flash hider to be permanently pinned...because as we all know that saves lives :/

It's not totally brazed on (I can wiggle the flash hider), just the pin is, I called the manufacturer and this is what they told me. It's 2/3-3/4 off to the side and I assume on a flat spot on the threads.

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I'll throw my vote in with the take a grinder to it group. Unless it's a particularly expensive flash hider......

Kp321 said:

What’s going to happen when you get the flash hider off? Will you instantly have an illegal SBR? Most pinned flash hiders are extending short barrels.
I will agree with the comments on using Oxy-Acetylene. Need to heat up fast to minimize heat damage, probably should use heat block paste also.

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Nothing illegal about having a short barrel. It just can't be on a rifle.

I had to remove one years ago to swap the handguard. A sharp drill in the drill press removed enough weld that turning over the barrel and giving it a smack on the backside of the pin, made it fall right out.

dfariswheel said:

Unless your'e trying to save the flash hider, the simplest and safest method is to saw and grind the thing off.

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I would probably just drill the pin away before I did that. It might not even be bonded all the way down, op said he can wiggle it in #8.

jmorris said:

I would probably just drill the pin away before I did that. It might not even be bonded all the way down, op said he can wiggle it in #8.

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That's where the grinder would be an easy way to go. Even if those pins are welded, the weld only penetrates less than 1/16". Only take a few seconds with a grinder. A lot of this depends on what kind of flash hider he has and whether he's trying to save it. Drill or grind are both gonna bugger up the flash hider, unless he's got a mill or some way to drill precisely. If he had that kind of capability though he probably wouldn't be asking the question.

109Hammer said:

Update: A dremmel made light work of it. They pinned it by offset drilling through the threads. I carefully cut out the pin. Unscrewing the flash hider recut the threads. Not pretty looking, but not worth sending to a smith IMO.

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Happy ending