Here is the simple and strait forward way to install our A-Hole Mk4a™ and A-Hole Micro™ Muzzle Brake.
As always, triple check that your weapon is NOT loaded before doing any work on your firearm. Make sure there is no live ammo anywhere near you and generally don’t be stupid. Follow the Commandments of Safe Firearm Handling and all will be well.
Clamping fixture for your firearm
Proper sized wrench for removing old muzzle device
3/4″ Crows foot wrench attached to an appropriate torque wrench
High temp Anti-seize – optional
Shim Kit – Included with your A-Hole™ Muzzle Brake
Once your weapon is proven to be unloaded, you will need to remove the existing muzzle device. If no device is present, then skip this step. It is highly recommended to have a clamp fixture to securely and safely hold your firearm while doing this. It can be very difficult to remove some factory installed muzzle devices. As such, you can damage your firearm if it is not properly held. Also, double check to make sure that your existing muzzle device was not permanently attached to the barrel. If you need help with this, take it to a qualified gun smith. To get the old muzzle device off, simply unscrew the existing muzzle device using the appropriately sized wrench or armorers tool, then place into storage or up for hock on eBay. If any sort of washer was used in the installation of your previous muzzle device, that will need to be removed. Crush washers can be a pain to remove after there have been crushed down. Do not cut the crush washer off as it could damage your threads and impede the installation of your new Arson Machine™ A-Hole Mk 4a™ Muzzle Brake
Once your old muzzle device has been removed, gently clean the threads with the wire and inspect the threads for any damage or deformation. If there are any issues with the threads, take it to a qualified gunsmith to see about repair.
Once the threads are good to go carefully thread on your new A-Hole Mk 4a™ Muzzle Brake. It is very easy to cross thread the A-Hole Mk 4a™ Muzzle Brake. It should thread on with ease. You should not need to use a wrench at this point. If you feel the need to use a wrench, something is not right. After it is threaded on, thread it by hand all the way to the shoulder of the threads. Note the rotational position of the brake. You want to orient it so that the Arson Logo is up. With the shim kit, the thicker shims will get roughly 90° of rotation, and the thinner ones will be 15-18°. Combine washers until the muzzle brake is about 20°-30° before its at proper orientation. This allows you to get roughly the proper amount of torque. Due to it’s aluminum construction, when tightening down our A-Hole Mk 4a™ Muzzle Brake it can be easy to over torque it and strip or over stretch the threads. As such, we don’t recommend exceeding 20-30 ft-lbs of torque when tightening the brake. In destructive testing we have gotten them above 50 ft-lbs of torque but it is not recommended. If that happens the muzzle brake might become very difficult to remove and it WILL get marred up by the end wrench, ruining the sweet, sultry looks of your brand new A-Hole Mk4a™ or A-Hole Micro™ Muzzle Brake. It may take several attempts to get the right combination of shims in place. Once you have the right shim combination, if desired, you can put a small amount of high temp anti-seize (not-included) on the threads of the barrel then finish off the installation by tightening your new muzzle brake into place with a 3/4″ open end wrench. To reduce the possibility of marring the finish you can also use and adjustable end wrench (aka crescent wrench) with the jaws wrapped with tape. If doing this, make sure that the adjustable wrench is tightened down as much as possible to the wrench flats at the rear of the brake. As the brake heats up, it may loosen. If so, add one more thin shim and re tighten.
It should be noted that when shooting, the hot gasses and unburnt powder will erode the finish on the inside of the brake. This is completely normal and will vary depending on the ammunition used. We currently have a test brake sitting at around 3000 rds of russian 223 and XM193 through it and still going strong. We have tested our A-Hole Mk 4a™ Muzzle Brake under full auto fire and plenty of rapid fire, but we do NOT recommend or rate it for full auto usage. We also do NOT recommend permanent installation of our A-Hole Mk 4a™ Muzzle Brake. It should stay easily removable in case of damage or wearing it out. DO NOT use any kind of thread locking compound on the threads when installing.