Muzzle Device Timing
Also: Shim · Crush Washer
Indexing a brake or other muzzle device so its ports sit level and symmetrical, achieved with timing shims or a crush washer.
Timing is the act of installing a muzzle device so it stops at the correct rotational position, with the ports clocked exactly where the design intends. On a muzzle brake the side ports must sit level and balanced so the gas vents symmetrically; a brake clocked even a few degrees off can push the muzzle sideways and disturb the shooter’s hold. The same logic applies to a flash hider with prongs that must clear the line of sight.
Two methods set that final position against the rifle’s muzzle threading. A stack of thin timing shims under the device lets the installer tune the standoff so the part torques up exactly square, the cleaner approach for a precision build. A single crush washer is simpler and deforms under torque to take up the gap, which is common but offers less precise control, so careful gunsmithing often favors shims.