• M4-SD Hammer Compensator Installation Instructions:
• 1.) Unload your Ar15 in accordance with its manufacturer’s user manual.
• 2.) Remove the bolt carrier group and charging handle from the upper receiver.
• 3.) Fixture the upper receiver in a vise using a polymer vise block.
• 4.) Use a ¾” wrench to remove the muzzle accessory.
• 5.) Remove the existing peel or crush washer (do not re-use).
• 6.) Grab the provided and new peel washer in a set of pliers, (preferably a set of pliers with smooth jaws so you don’t damage the thin layers of the washer).
• 7.) BEING CAREFUL NOT TO BURN YOURSELF- Hold the washer over the burner on a stove or the flame of a torch until one side of the washer glows red for 10 seconds.
• 8.) Drop the washer on a steel surface such as a baking sheet, or hang it on the blind muzzle threads of the weapon to air cool- do not water quench.
• 9.) Wait 5-10 minutes to cool
• 10.) The peel washer should now be separable into one thick washer and ~15-20 thin washers.
• 11.) Install the M4-SD tactical compensator using the thick washer and enough thin washers to clear the thread run-out on the barrel so that contact is between the washer, compensator, and thread shoulder, not between the compensator and barrel thread run-out. Place the thin washers toward the upper and the thick washer closest to the compensator- this will provide the greatest insurance against damage to the very thin washers during repeated tightening and loosening of the compensator required to obtain proper torque and alignment.
• 12.) Tighten the compensator to approximately 35 foot lbs (or about 2-3 o-clock positions from hand tight to the wrench-tightened and aligned configuration). If the compensator is not aligned properly, add or delete thin washers as necessary to obtain proper alignment. You may have to tighten, loosen, add shims, and re-tighten the compensator as the shims may flatten out initially, reducing torque necessary over the long term to secure the compensator.
• 13.) If you have a suppressor to mount to the compensator, do so at this time, visually confirm alignment by placing white paper in the breach, looking through the suppressor bore, parallel to the walls of the rifle bore on all sides, comparing clearance to elements of the suppressor bore.
• 14.) In some cases alignment may not be true, due to production barrel thread inadequacies. In these cases a single very thin [~.001” thick] shim from the peel washer can be cut in half using a scissors and used to force better alignment conditions to be met. The procedure for that is as follows- loosen the compensator ½ - ¾ turn, insert the [additional] half moon shim in between the shims on the side with the most clearance and carefully tighten the compensator confirming the shim remains in the proper location- re-clock the compensator to proper orientation and recheck suppressor alignment. If alignment is now near perfect or visually perfect, you have successfully installed your compensator and now have a suppressor ready weapon.
• 15.) If alignment is not perfect continue to attempt a solution. If no solution is possible, there is a chance your barrel thread was bad from the factory. In this event you may have to have the barrel re-threaded for suppressor use. We recommend ADCO firearms in Sylvania Ohio for suppressor thread work. They are located on the internet at www.adcofirearms.com

⚠ WARNING: This product can expose you to chemicals including lead, which are known to the State of California to cause cancer and reproductive harm. For more information go to: www.P65Warnings.ca.gov.