I am having a knockdown drag-out fight with a buddy who states that a rifle that has a barrel under 16 inches is OK as long it has a flash hider that brings it to legal length, but HE believes this flash hider does not have to be permanently affixed (just firmly screwed on.

Now I know that the muzzle device must be permanently affixed to bring the barrel to a PERMANENT 16" length in the case of a sub-sixteen inch barrel, but I can't prove it.

I can't find any regs in the NFA, GCA or any other law that states specifically that a sub- sixteen inch barrel is permitted on a non-NFA rifle only if the extending muzzle device is permanently affixed.

Does anyone  have a reference or know where this might be found? It must be true, otherwise why is everyone welding the flash hiders on their 14.5" M4 barrels to come to 16"? I just can't prove it with BATF documentation.  Any help is appreciated.

Have him configure a gun in this configgeration, and take it to ATF to prove he's right!

BATF section 478.11

That gives the definition of a SBR including the 16" barrel length. Something attached to a barrel that is not permanent  is NOT part of the barrel. If you duct tape a coat hangar to the end of your 7.5" upper and put a rear stock on it I don't think the ATF is gonna be OK with that. Simply threading on a flash hider is doing the same thing. Silencers are not considered part of a barrel either. Why not? because you can simply unscrew the thing and have an SBR.

I don't think you are going to find a section of the regulations that says a sub-sixteen in barrel is permitted on a non-NFA rifle only if the extending muzzle device is permanently attached.  The reason is, because when the device is permanently attached its part of the barrel and no longer a 'device' and if it is not permanently attached it IS a 'device' and not part of the barrel which means the length is measured WITHOUT the device.

It's an ATF interpretation of te statute.  If your friend want's evidence that that's how the Feds view it, here it is.

Edited to add:  Like bumpOx said, if it's not permanently attached, it's not considered part of the barrel.  


Edited again to add:  As far as I can tell, there's nothing about this in the CFRs either.  It appears to be purely a matter of ATF interpretation, and not the product of any formal (i.e., published in the Federal Register with opportunity for public comment, etc.) rule-making procedure.  

Thanks guys, I think that gives me enough ammo. Especially the part about not being "part of the barrel" if it is not permanently attached.

From Bardwell's Legal Opinion Website, is this letter covering permanently attaching muzzle devices to legally lengthen barrels. Also was in context of the Assault Weapon Ban and threaded muzzles, but both are addressed in Official reply from BATF.

BATF Letter on permanently attaching muzzle devices

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.

This website is FULL of documented legal info straight from BATF Tech Division. Very useful.

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Lonny