Workbook

LESSON 211: INSTALLING A MUZZLE CONTROL DEVICE

(Revised 09-01-99)

To the best of my understanding, the current rules prohibit exposed threads on a rifle, as it would permit the

easy attachment of a flash hider. While "flash-hiders" are forbidden, "muzzle control devices" are

specifically allowed. As I read the rules, you may thread the muzzle, so long as you then permanently attach

the muzzle control device. "Permanently" can include welding, high temperature silver solder (1100 degree

or higher melting point), or pinning. If pinned, the pin must then be welded over or a "one-way" pin that

cannot be readily drifted out. A permanently attached muzzle device is included in determining overall

barrel length (minimum 16").

The AK-74 brake that is available for the 7.62x39 AK works well and is inexpensive and already threaded

for metric guns. If you get a true AK-74 brake, designed for the 5.45mm round, insure it is bored out to

>.315". The original Belgium Style or Argentine/Brazilian style brake seems to comply with the definition of

"muzzle control device" versus "flash hider" and is what I recommend. It does have a bayonet notch.

Although a "notch" is not a "lug" you may wish to remove enough material from the rear of the brake to

eliminate this feature. The DSA Brake is nice, fits well, and is loud. I recommend it also. The Hesse Arms

units are supposed to be a slip-fit, but usually have too small an internal diameter and need to be enlarged

before soldering in place. . Coincidentally, they are usually small enough to thread internally 15mm x 1.0

(HK) and the barrel is wide enough to thread the same without turning it down. While you won't have the

desired 60%+ thread engagement, it is enough to hold it in place and gives a great grip for silver solder. The

Smith Enterprises brakes are horrible and I don't recommend them at all. They are in three pieces, so each

part must be welded, pinned, or soldered and you have four unsightly wrench flats remaining.

PINNING A MUZZLE CONTROL DEVICE

I have found the pinning way to be easy only if the muzzle device is not hardened metal. Screw the muzzle

device on and index. Split washers or lock washers may be used to obtain proper index. Drill a hole that

intersects both the inside of the muzzle device and the outside of the barrel. Drill this hole almost, but not

quite all the way through. Then drive a pin into this hole, preferably a tapered pin. Now, you cannot pound

the pin out from the other side because the hole doesn't go all the way through (thus a "blind" hole). The

problem is trying to drill a hole on the edge of a round object - the drill bit has a tendency to walk. The

solution is to first cut a tiny flat, then center punch it to create a divot that the drill bit can grab onto and not

slip. Grind the end of the pin flush and touch up. A drill press is helpful, but not required. The only way to

remove it is to cut it off, or drill the pin out, neither of which count as "readily convertible". If you have

drilled all the way through, you must then weld up one or both sides, file to fit, paint to match.