Depends on the age of the gun.
Late compensator's appear to be pinned similar to the original SMG guns.
This is easy to ID. There will be a solid pin through the compensator just below the sight, through the larger diameter section at the rear of the brake.
Push out the pin from Left to Right.
If you need to remove the sight blade itself, remove the pin FIRST.
Turn the compensator with a synthetic strap plumber's strap wrench.
Earlier compensator's are attached with epoxy or thread locker.
These are identified by not having a pin.
These must be heated up to around 300 degrees until the compound degrades, then removed, cleaned of all the compound, then re-attached with new locking material.
DO NOT over heat. All that's needed is about 300 degrees of heat. Overheating is NOT good, and can damage the blued finish.
To assist in turning the compensator off, pad a LARGE pair of curved jaw Vise-Grips with copper or brass protectors to protect the finish on the brake.
Warm the brake and barrel with a small torch, being careful to NOT overheat.
Use the Vise-Grips to attempt to unscrew the brake until it does start to turn, then lay aside the torch and unscrew the brake from the barrel.
Allow everything to cool, then use Acetone or lacquer thinner to dissolve and remove the residue or whatever the adhesive was.
I recommend Loctite RED (permanent) to reattach the brake.
Degrease the brake and muzzle threads and apply a coat of the Loctite.
Thread the brake on, then before it sets up and locks the brake in place, shoot a quick group to get the sight on target, then being careful not to move it, allow 24 hours for the Loctite to fully cure.
Once cured, scrub the compensator and barrel inside and out, with hot soapy water to remove any uncured excess, and apply lube to prevent rust.
