What is an Acceptable Weld?

[Adam123]

I've been searching, to no avail, for the specifics on how a barrel extension/brake should be welded in order to please the ATF. I plan on doing 12/3/6/9 o'clock welds. Can someone please point me to a tutorial, photo or more specific information on what is considered a proper and legal weld? Any BATF links would be GREATLY appreciated.

In other words, I don't want my weld to be too small. Then again, for aesthetic reasons, I definitely don't want the welds to be too big.

I'll also add that I was considering silver soldering, but I don't like the idea of applying that much heat to my firearm. I plan on removing the extensions once I get my tax stamps and I am assuming that it will also take a substantial amount of heat to remove the extensions. This worries me.

Thanks in advance for any assistance.

 

[drsfmd]

Call the ATF.

 

[rcmodel]

A blind pin is generally used.

The hole is drilled through the muzzle device, through the edge of the barrel, leaving a semicircle hole on the barrel surface, but not all the way out the other side of the muzzle device.

Then the pin is driven in, and then a spot weld is put on to close the hole.
After dressing the weld down & finishing, it is invisible.

rc

 

[X-Rap]

I went with a 100% tig weld on mine, just didn't want some cop/agent ever putting a wrench on my brake and trying to unscrew it.
The tig weld is clean if you just fuse the parent metals and don't add any filler metal.
If you are getting a stamp I would just leave it disassembled and maybe store tha barrel with a non AR owning friend rather than have to grind/turn welds to find a pin or clean up the barrel.

 

[drsfmd]

If they decide to put the wrench to it, you better hope the barrel twists or something breaks before the brake comes off.

Full round weld is the best way to go. It's supposed to be non-removable after all.

 

[dfariswheel]

Here's the AFT standards on welds and muzzle attachments:

March 31, 1998

BATF
Firearms Technology Branch
Washington, DC 20226

Greetings:

I had some questions about permanently attaching muzzle brakes
and barrel extensions to firearms.

As you are aware, some barrels, particularly for some semi-
automatic rifles, come with muzzle threads. However, it may be
necessary, depending on the other features of the rifle, to remove
those threads, in order to keep the firearm from being considered
a "semi-automatic assault weapon". Additionally, some firearm
barrels come in lengths below 16 inches, and in order to be
installed on rifles without making the rifle subject to the
National Firearms Act, an extension may be permanently attached to
the end of the barrel, by muzzle threads, so as to make the barrel
length at least 16 inches.

I was wondering what methods of attachment to muzzle threads
are considered permanent enough so as to either extend the barrel
length, by use of an extension, or to remove the muzzle threads as
a feature of a semi-automatic rifle which might otherwise be
considered a "semiautomatic assault weapon"

In particular, I have heard that welding is acceptable. If you
can, please advise me of the method of welding, and the required
weld coverage. I have also heard that high temperature silver
solder is acceptable. If you can, please advise me as to the solder
alloy, and melting temperature that would be considered permanent.
I have also heard that some industrial adhesives are acceptable, in
particular a product called "Rocksett". I would appreciate
confirmation as to which, if any, industrial adhesives have been
found to be acceptable.

Also, if there are any other methods which I have not
mentioned above, which have also been found to be acceptable
methods of permanently installing muzzle devices onto rifles, I
would appreciate it if you could advise me of what they are.

Sincerely, XXXXXXXXX


DEPARTMENT OF THE TREASURY
Bureau of Alcohol, Tobacco and Firearms
Washington, D.C. 20226

JUN 18 1998 F:FPD:FTB:RAT
3311

Dear Mr. :

This refers to your letter of March 31, 1998, in which you ask
about permanently attaching a muzzle device to various firearms.

A muzzle device, such as a muzzle brake or barrel extension, which
is attached to a barrel by means of welding or high temperature
silver solder having a melting point of at least 1,100 degrees
Fahrenheit, is considered to be part of the barrel for purposes of
measurement. A seam weld extending at least one-half the
circumference of the barrel or four equidistant tack welds around
the circumference of the barrel are adequate for this purpose.

A firearm having a muzzle brake, cap, or barrel extension
permanently attached by those same methods to cover the threads on
a barrel, would not be considered to have a threaded muzzle.
Please note, however, that any muzzle device or barrel extension
which functions as a flash suppressor or grenade launcher would
still constitute one of the qualifying features of a semiautomatic
assault weapon as that term is defined in 18 U.S.C. section
921(a)(30(B). Industrial adhesive products are not an acceptable
method for permanently attaching a muzzle device.

Mr.

We trust that the foregoing has been responsive to your inquiry.
If you have further questions concerning this matter, please
contact us.


Sincerely yours,

[signed]

Edward M. Owen, Jr.
Chief, Firearms Technology Branch

 

[rjrivero]

If they decide to put the wrench to it, you better hope the barrel twists or something breaks before the brake comes off.

Please show me a citation that shows the barrel twisting or something breaking to be part of the definition of permanently attached muzzle device.

The letter quoted above is essentially from ATF 5320.8 chapter 2.

 

[drsfmd]

Please show me a citation that shows the barrel twisting or something breaking to be part of the definition of permanently attached muzzle device.

"permanently" means just that... the attached device better not be the first thing to let loose, or it's not permanent.

 

[X-Rap]

Can anyone tell of a instance in which the method of fastening was tested? Do they just take your word for hi temp solder, blind pining if there is ever a question?
For me the weld was the simplest surest way to avoid any question in the present or future should the barrel ever change hands but it would be interesting to hear what the standards are to test.
My situation was, I bought a gun used from a shop and upon taking it home and setting it in the safe it was shorter than the other carbines. Measured and discovered it was 14.5 with 2.25 Phantom fs on it.

 

[dfariswheel]

If you're at the point where a Federal officer is testing how well you attached a muzzle attachment, you probably have far more serious problems to worry about.

I've never heard of any case of a barrel attachment being tested for how secure it is.

 

[Jim K]

I always wonder why it is so necessary to have such short barrels in the first place. Is it just to push the envelope in hopes of attracting the attention of BATFE? Does someone really think that is a good idea or that they will "have fun" pi**ing off the Feds? Those who think that way soon find out that a ticked off cop, even one in a suit, is not a good person to have around.

Or is it matter of having some kind of bragging rights over who has the shorter barrel, sort of like who has the longest... well, never mind.

Or of looking like those fake "cops" or phony "soldiers" in the gunzine ads. I could probably look ferocious too, if I can get $250 an hour posing in black spandex.

Sure, short barrels are convenient, but does an inch or two make that much difference? Not that I can see.

Jim

 

[kingcheese]

If it where me, id use a blind pin, i don't really like the looks of globs of weld on a barrel, but id be paying a smith to do it

 

[X-Rap]

If a smith does it and leaves "globs" of weld then he is no smith. Tig welding is very clean and present on many firearms.
As to blind pining the above copy from the ATF doesn't mention it, I know it is done but there must be a standard for it as well. The diameter of the pin will be a factor and if a weld every 1/4 is required I am curious as to what they will say about pin size. Another thing would be how to satisfy an agent inspecting the gun if it is pinned and dressed back to OG finish.

 

[dfariswheel]

There is no spec on the size of the pin.

Again, I've never heard of any firearm being tested by a Federal agent to determine how well the attachment was mounted, nor is it really possible to come up with a field test.
If the test is that the attachment can't be removed, how much force would be used in the test?
Is the agent supposed to apply a wrench and try to unscrew it? How hard can he twist the wrench?
Should the agent be a 100 pound woman or a 250 pound former line backer?

The Federal standards simply mandate the use of silver solder (braze) that melts at over 1100 degrees, welding as stated above, or inserting a blind pin.
Do any of these correctly and it will take excessive force to try to break the attachment loose. That's good enough for Government work.

 

[mr16ga]

Get a 16" barrel and shoot that until you get your paper work then put the original barrel back on. Don't even give the cops a reason to have a look.

if you do weld then you use a lath to take the welded part off not a torch.

 

[mr16ga]

Sure, short barrels are convenient, but does an inch or two make that much difference? Not that I can see.

Jim

It is not in the seeing.