The Chief, Firearms Technology Branch of the ATF (Edward M. Owen, Jr.) says in a [url=http://www-2.cs.cmu.edu/afs/cs.cmu.edu/user/wbardwel/public/nfalist/atf_letter40.txt]letter[/url] that to [b]increase barrel length[/b] and/or [b]remove muzzle threads,[/b] you can attach a muzzle device (such as a muzzle brake, cap, or barrel extension) by:
1) high temperature silver solder having a melting point of at least 1,100 degrees
Fahrenheit.
2) A seam weld extending at least one-half the circumference of the barrel, or
3) four equidistant tack welds around the circumference of the barrel
Mr. Owens goes on to say, [b]"Industrial adhesive products are not an acceptable method for permanently attaching a muzzle device."[/b]
In this letter, Owens does NOT say whether or not drilling a hole through the muzzle device into the barrel, pinning it, and tack-welding over the pin is acceptable. It is common practice to do so (Kurt does this), and Mr. Owen might have approved such a method in another letter. However, I couldn't find anything in writing for this. Anyone?
I attached a couple of muzzle brakes using high temp silver paste similar to Silver Fusion by Brownells.
[img]http://bin.homestead.com/files/solder01.gif[/img]
I use a crush washer instead of a peel washer.
[img]http://bin.homestead.com/files/solder02.gif[/img]
Torch until it is dull red. Propane probably is not hot enough. Use at least MAPP.