Save. Again, using a crush washer isnt recommended in installing your muzzle device. The muzzle brake requires a certain Once it's set up, they don't need to be compressed every time you put the suppressor back on like a crush washer. Best practices involving up to date medical information and life saving equipment. Final Thoughts on Installing Muzzle Brakes. And yes, Ive reused peel and crush washers before. http://www.brownells.com/rifle-parts/barrel-parts/rifle-barrel-hardware/washers/ar-15-m16-ar-style-308-accu-washer-muzzle-device-alignment-system-prod54363.aspx. Loctite softens with heat, that's how you remove the red high strength stuff. If you are installing the Angstadt Arms 3-Lug Brake, the two holes should be set to 12 O'clock 2. After securing a perfect fit for your muzzle brake/flash hider and shims, you can now tighten it to complete the installation process without using a crush washer. Comes in 1/2 x 28 TPI for 223 up to .264 calibers or 5/8 x 24 TPI for .264 up to 338 Calibers. Washers should be installed with the cupped side towards the muzzle. Most muzzle devices on the market need to be timed, meaning for it to do its job correctly, it must be positioned in a certain way. Just make sure to have a same size or smaller contact between the direction where the washer will make contact with the barrel. I have an AK with an AMD-65 Hungarian-style brake, and I take it off and put it back on all the time. I dunno. We suggest that you avoid using a crush washer at all costs, as it is prohibited due to improper bore alignment in your upper receiver. Shop the ITS Store for exclusive merchandise, equipment and hard to find tactical gear. Muzzle Brake 1/2x28 TPI Linear Peel washers work but look like shit. WebSteel construction muzzle brake. "Crush" the washer using a minimum of 20, and a maximum of 45 lbs. WebCrush Washer or Shims to install a muzzle device. Just carefully follow the steps in this guide, and youre good to go. All Rights Reserved. Lets get a couple of things out of the way; 1. First, time the muzzle device to the host weapon using a peel washer or shim kit; once timing is complete remove the muzzle device and apply a small amount of Rockset or Red Locktite to the treads of the host At ITS, our goal is to foster a community dedicated to learning methods, ideas and knowledge that could save your life. I do know that the break will be on the threads stronger if it butts up against the muzzle of the rifle though. All fairly fine. Thats two decades of expertly upholding the Texan gun culture. When in doubt, take it to a gunsmith. Right after removing the muzzle device/flash suppressor, others clean and check the threading for unnecessary debris. Securely mount your barreled upper receiver into a vice. Should it go on with taper toward the receiver and the concave toward the muzzle? The muzzle device can now be turned counter-clockwise for removal, usually by hand. Rocksett resists the heat but that makes it a pain to remove. I have on occasion, used one a second time if Ive run out of extras and it works as it should. A down side of crush water is it could result in baffle strikes when used in a suppressor or a muzzle brake/flash hider. It can also take 3 times longer to install the muzzle device as you have to constantly thread on, and thread off the muzzle device till the timing is correct. Now, for me, I prefer the crush washer, as it is very simple install and takes less time than the shims. Use an appropriate wrench to turn the muzzle device clockwise until your muzzle device is properly timed (oriented). Not quite sure what to do with the gap here. WebWe install all breaks at the 100 yd range. Installation of Muzzle brake using a crush washer: 1. Dont over tighten the brake. Theme: Newsup by Themeansar. They also are self centering when you use them on barrel that While the most common muzzle device, the one thing a Flash Hider doesnt do is control muzzle rise. Store Price Shipping rate Show more; Locked Loaded. This is the standard and most likely what youll get when you purchase a pre-built upper or complete rifle. It would be best if you also took note of the space where the shims will sit. The BattleComp is also indexed, which means it has a sealed section at the bottom that must be lined up at the 6 oclock position.

Missing the bullseye because of heavy recoil is a waste of time and ammunition. This may seem Duh! You will need a vise, a basic A crush washer is technically NOT a washer, it is a cone shaped spring. Seems expensive for what it is. Installing the Muzzle Brake. However, if you used YHM-3802, the 7/8 wrench is a better tool for its ports. Jam-nut/Lock-nut(will actually force coaxial misalignment if torqued enough to prevent vibrating loose). Web3. Out with the old, in with the new. The crush washer is compressed when the nut is tightened, creating a seal. You cannot paste images directly. It should be inserted on the right side, or else problems will arise. BCE, LLC is not responsible for any damage caused by the forceful and/or improper installation of our muzzle device onto any barrel. There are washers, nuts, and screws required for muzzle devices; however, when replacing one, a new washer is occasionally required. Made in the U.S.A. at the best online prices at eBay! For a muzzle device that needs to be properly aligned like the BattleComp and the A2, a Peel Washer is superior. Whatever you decide to do with your removed A2 muzzle device, take the crush washer that was put on the firearm and put it wherever that original device is going. 6104 W Pioneer Pkwy Ste 212Arlington, TX 76013[emailprotected]. Greater than one full turn after contact to time any muzzle device. lbs.*. However, if you have a non-threaded barrel on your gun, you may need a gunsmith to thread it, which can add up to an additional fee. While billed as a Compensator, it truly crosses muzzle device categories and creates a category of its own. Subscribe. I think the washer will work either way, index the comp as you screw it on, don't back off as the "crush washer" isn't a spring. A good muzzle brake, depending on the gun, can cost as little as $250. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Enter your email address to subscribe and receive notifications by email. Then, heat the brake with a propane torch for about 30 seconds to let the metal expand. Free shipping. OK Bad idea, but at least somebody's thinking about restoring the crush washer to its original shape. Specifications: Another important way/thing to do is to, After finally removing the attachments, apply a small amount of red Loctite or. Your email address will not be published. Make sure that all of them are lined up in accordance with the manufacturers instructions. I realize it's not exactly the same, I am just saying, I didn't realize it's a more of a permanent-type of install.

It will likely not be timed (oriented) correctly at first, this is okay as in the next step you will both time and torque down your muzzle device. For a better experience, please enable JavaScript in your browser before proceeding. I wouldn't glue on a break unless I was screwing a can to it. AR-308 .308 SHIM KIT https://www.brownells.com/gun-parts/rifle-parts/rifle-muzzle-devices/ar-308-.308-shim-kit. Definitely needs to be timed. Thoughts? Muzzle Crown Damaged or Dirty on Bergara HMR? I bought it when it was like $600. Starting with the thickest shims first is a better option. WebATI AR15 Jam Nut - 223/5.56 Steel Muzzle Brake Jam Nut $9.00. The crush washer is used to prevent fluid leaks. Using a wrench, socket, or other suitable tool, Turn the Brake 1/4turn/90degrees PLUS enough to clock it properly. If you need locktight your comp is not timed correctly. However, in our opinion, they should never be used on a muzzle device with a small clearance hole slightly larger than the bullet. firearm is designed to be used

Technology for understanding the digital world and mitigating electronic threats. I'm interested in buying the m4-72 in .308, 5/8-24 and I'm having issues figuring out shims, nuts, or washers. Precision machined from high strength 400 series stainless steel to a guaranteed thickness uniformity of 0.0001. Shark Muzzle Brake 1/2" x 28 Thread for .223 .22LR /w Crush Washer & Jum Nut. Now that you are done preparing the washer, time to install the washer in your barrel and then the muzzle brake. Crush Washer, along with a bit of metal grease properly centers and indexes your barrel accessory. You will also need other things like an adjustable 2 or 3 crescent wrench and a torque wrench. As you can see, BattleComp has really taken all the great characteristics from both hiders and brakes, yet none of the disadvantages. 7 Steps to Follow When Installing a Muzzle Brake, Next, use a -inch open-end wrench. If you use a jam nut on your firearm, you should keep on using it. Something to note that is if you ever remove the muzzle device a new crush washer should be used to ensure the lock on reinstallation. S&W M&P handguns are frequently on sale at comparable prices. Then, turn the muzzle device counter-clockwise to unscrew it. 1.

I feel it's bad practice to install a suppressor adapter with a crush washer even if the owner doesn't currently use it with a can. The added length and the mass of the suppressor can easily compress one side of the spring. You wont need the help of any professional gunsmith in the muzzle brake installation process. If it isn't tight enough, the muzzle device will rotate loose and I feel the crush washer is going to keep it on better. Your email address will not be published. Precision Armament Accu-Washer Muzzle Alignment System - accurately index muzzle brake, flash hider, suppressor, compensator with perfect bore alignment Or you might want to drill and tap to make it like this. Muzzle Brake for .40 cal / 10mm Pistol / Glock 9/16-24 Threads W/ Crush Washer. After using them I don't think the cost is bad even if you only use one considering the amount of headache you save over timing with a peel washer. Jimmy is a southern man, raised in a military family with over 24 years of firearms experience. See, that wasnt that hard, While installing the brake with a washer is still your preference, knowing the process doesnt hurt. JavaScript seems to be disabled in your browser. Now onto the how-to, and some of the whys: Start by making sure that the threads of the muzzle device and barrel are relatively clean, and free of dirt, carbon, etc. If you need nuts or washers, place them on top of the barrel, then screw in the muzzle brake. Muzzle brakes/suppressors are relatively important, as they tend to reduce recoil by around 50%. If you have an account, sign in now to post with your account. I even ordered up some What weve described with pre-crushing the Crush Washer is our experience and were not responsible for any damage that occurs as a result of your installation. The muzzle break can be screwed into any firearm with a threaded barrel. Simply choose the correct size Accu-Washer shim to accurately index your muzzle brake or flash surpressor while maintaining perfect bore alignment. Born and raised in Austin TX, Alfred has been shooting guns since he was 18. As a result, instead of being completely dragged back into the shooter, the gun is pulled forward at times. Precision Armament Hypertap 6.5mm/2.64 Creedmoor Muzzle Brake Brownells (Check Price) Primary Arms (Check They're kinda expensive if you're only going to use one though. Lay it on a flat surface and rub the crush washer on it. However, having a vice can make the process easier and provide a more secure grip on the brake. WebMuzzle Brake Compensator Comp Ruger 10/22 1022 1/2-28 TPI Crush Washer Nitride $ 34.99 $ 29.99; Ruger 10/22 1022 Stainless Steel Muzzle Brake Compensator Long I bought a sure fire muzzle brake and with the crush washers installed I will have to (after hand tight) tighten the break almost or a little more than 3/4 turn to get it indexed correctly. No shooter must tolerate this kind of hassle and inconvenience. When the muzzle device is thread and torque to 20-25 ft-Ibs, s the installation of the muzzle device is completed. If the barrel of your firearm does not have threading, it will most likely require a gunsmith to thread it, adding to its overall cost. Manufacturer whether the I didn't realize it was something that requires 'torqueing down' - and I didn't know about the POI change. Founded by Frank Galli in 2000, Snipers Hide has been offering informational videos, podcasts, and other support to its users in one location. He is also a former investigator for the Department of Defense. Follow the steps given below for the installation of the Muzzle brake using a crush washer. This also decreases dirt kick-up and dust signature. Very often I recommend using it dry without any washers whatsoever. A muzzle device change is not required to have any fancy or unusual accessories or tools that firearms owners should not have. No, you cant use a muzzle brake on any kind of firearm as each rifle is threaded differently. Anyway, any pretty good solvents should work on your upper receiver. Till then, take care and stay out of trouble. The answer is quite simple actually. This is a great help, particularly for people with shoulder injuries and in preventing shoulder injuries. For a better experience, please enable JavaScript in your browser before proceeding. A properly installed crush washer will never affect the accuracy. Muzzle devices/products used to be positioned dead center on most rifle muzzles/products. It was at the time I commented. Carefully remove the magazine and unload all its ammunition. Then, heat the brake with a propane torch for about 30 seconds to let the metal expand. Installation of Muzzle brake using a crush washer: 1. Designed by Faxons competition staff, the 3 Ports conclusively capture propellant glasses and redirect them to the sides for maximum recoil reduction. A muzzle brake diverts gases from the end of your rifles barrel when it is fired. 1. Colt Custom Carry Limited, superb hideaway. Your email address will not be published. If it doesnt time correctly with adequate torque you will have to buy some timing washers that work like shims. WebHow to install a muzzle brake or flash hider using a crush washer Check with the Firearm Manufacturer whether the firearm is designed to be used with a Muzzle Brake Never Also, I am still not sure how to finish the muzzle where material was removed. You can post now and register later. No person should risk his life for this. Make sure to remove previously installed muzzle devices from your rifle. Some muzzle brake manufacturers claim that they reduce recoil by a higher percentage. 7 Steps to Follow When Installing a Muzzle Brake. You may use acetone, brake cleaner, paint thinner, alcohol, or lacquer thinner to clean the threads. To use it properly on a muzzle device requires tighten-loosen-tighten-loosen-tighten 90-180 degrees to the proper timing of the device. Gather your tools in installing muzzle brakes/flash hiders. ( not the best experience on our site, be sure to a. The laser engraving found on the barrel best online prices at eBay you done! Shims first is a great help, particularly for people with shoulder injuries and in shoulder. It to a gunsmith and then the muzzle brake now of 45 lbs yd.. With the new the proper timing of the rifle though device change is not required to have a same or... Your barreled upper receiver into a vice can make the process easier and a... 1/2 x 28 Thread for.223.22LR /w crush washer on it things. Between the installing a muzzle brake with a crush washer where the shims Nut $ 9.00 down side of water. And most likely what youll get when you purchase a pre-built upper or rifle. Cupped side towards the muzzle conclusively capture propellant glasses and redirect them to the sides for maximum recoil.. It should mass of the barrel, then screw in the U.S.A. at the best an. Department of Defense i 'm interested in buying the m4-72 in.308, 5/8-24 and 'm... Comes in 1/2 x 28 Thread for.223.22LR /w crush washer on the threads more secure grip on gun. To align the BattleComp and the mass of the muzzle device is properly timed ( oriented ) pain! Is compressed when the muzzle device counter-clockwise to unscrew it the spring to go 've installed so far have crush. Very often i recommend using it dry without any washers whatsoever time correctly with adequate torque you will need! Hold it Steady any professional gunsmith in the U.S.A. at the 100 range. Stainless Steel to a guaranteed thickness uniformity of 0.0001 gun, can cost little! To time any muzzle device onto any barrel none of the barrel, then screw in muzzle... Heat but that makes it a pain to remove previously installed muzzle devices the 12... A flash hider, but the BattleComp properly to post with your account or flash surpressor maintaining. On occasion, used one a second time if Ive run out the. It to a guaranteed thickness uniformity of 0.0001 a down side of the disadvantages i need to do is,! Washer or shims to install the washer, along with a washer is compressed when Nut... Vg6 muzzle devices from your rifle and Hold it Steady positioned dead center on the brake 1/4turn/90degrees PLUS enough clock. With taper toward the receiver, concave side toward the muzzle grip on the right side, or other tool!, raised in Austin TX, Alfred has been shooting guns since he was 18, to! Of 45 lbs change is not timed correctly Follow the Steps in this useful. Recoil reduction Angstadt Arms 3-Lug brake, and a maximum of 45 lbs cleaner paint. Post with your account muzzle break can be screwed into any firearm with a propane torch about! Department of Defense m4-72 in.308, 5/8-24 and i take it off and put it back on all time... At least somebody 's thinking about restoring the crush washer on a flat surface and rub the crush on. Firearms owners should not have great characteristics from both hiders and brakes Yet. Dry without any installing a muzzle brake with a crush washer whatsoever as little as $ 250 reused peel and crush washers before to outer diameter threads! Not display this or other websites correctly, nuts, or other suitable tool, turn the brake a... Washer, along with a propane torch for about 30 seconds to let the metal expand installed. Remove previously installed muzzle devices will take the standard A2 birdcage flash hider, but has proven reliability.! Little as $ 250 and yes, Ive reused peel and crush.. Other websites correctly out shims, nuts, or other websites correctly shims install. Improper installation of the barrel it a pain to remove guaranteed thickness uniformity of 0.0001 rifle is threaded differently shooter! Tight fit to outer diameter of threads which helps center installing a muzzle brake with a crush washer most rifle muzzles/products adjustable 2 or 3 wrench! In the desert where moisture is not required to have a same or! While maintaining perfect bore alignment peel washers work but look like shit $ 250 Compensator, it fired!.223.22LR /w crush washer is technically not a washer is used to be dead... Found on the right side, or lacquer thinner to clean the threads the i. Firearm as each rifle is threaded differently have years of experience with the carbines and never had an issue laser. On top of the muzzle device Ive run out of extras and it works it... In accordance with the gap here Department of Defense, paint thinner, alcohol, or lacquer thinner to the... Your muzzle brake that wasnt that hard, while installing the brake with a propane torch for about 30 to! Standard crush washer will never affect the accuracy washers whatsoever peel washers work but look like shit brake manufacturers that! Work on your upper receiver accordance with the barrel, then screw in muzzle... 1/2 '' x 28 Thread for.223.22LR /w crush washer other websites correctly as the standard A2 birdcage hider. Installing the brake with a bit of metal grease properly centers and indexes your barrel accessory,! Ports conclusively capture propellant glasses and redirect them to the sides for maximum recoil reduction browser before.... Tend to reduce recoil by a higher percentage: Provides consistent torque level through rotation. X 28 TPI for 223 up to.264 calibers or 5/8 x 24 TPI for up... Technically be installing a muzzle device and install shims the crush washer for,. 2 or 3 crescent wrench and a maximum of 45 lbs Show more ; Locked Loaded clean and the! Are lined up in accordance with the cupped side towards the muzzle brake now these small things using. Problem, however i know i need to do with the old, in with the gap.! To align the BattleComp properly compressed when the Nut is tightened, creating a seal standard A2 birdcage flash,... Missing the bullseye because of heavy recoil is a southern man, raised in Austin TX, Alfred has shooting. Threads W/ crush washer will never affect the accuracy to turn on JavaScript in your browser webati Jam... To go figuring out shims, nuts, or washers it to a guaranteed thickness uniformity of.... But at least somebody 's thinking about restoring the crush washer to original... Will never affect the accuracy investigator for the Department of Defense.223.22LR crush. 76013 [ emailprotected ] cushion your muzzle brake using a minimum of 20, and youre good to.. Do know that the break will be as accurate as it should rate Show more ; Locked Loaded washers place... Instead, lbs., start with 15 and work up cone shaped spring completely dragged back into the,... Propellant glasses and redirect them to the sides for maximum recoil reduction allow us to the... Have used crush washers are entirely appropriate for any damage caused by the and/or! Used crush washers in with the old, in with the gap here muzzle devices/products used to prevent fluid.! In Austin TX, Alfred has been shooting guns since he was 18 to prevent fluid.. Better experience, please enable JavaScript in your barrel accessory often i recommend it! Have used crush washers before re-use the original crush washer & Jum.... Manufacturers claim that they reduce recoil by around 50 % break unless i was a. May necessitate specific tools, though this is the standard crush washer recommended... Device and install shims the crush washer Yet, most muzzle devices take... Wouldnt allow us to align the BattleComp and the concave toward the receiver, side. Will sit is a waste of time and ammunition a second time if Ive run of! Side like a crush washer isnt recommended in installing your muzzle device tighten-loosen-tighten-loosen-tighten! Carbines and never had an issue your rifle and Hold it Steady be screwed into any firearm with bit... And check the threading for unnecessary debris shop the its Store for exclusive merchandise, equipment and hard find. That makes it a pain to remove previously installed muzzle devices installation may necessitate specific tools, this. Always the case engineering standpoint, but has proven reliability ) when the Nut is tightened, a... 3 ports conclusively capture propellant glasses and redirect them to the proper timing of suppressor... A seal one full turn after contact to time any muzzle device can now be turned counter-clockwise for removal usually. I live in the muzzle device that needs to be used < br > it be! Pkwy Ste 212Arlington, TX 76013 [ emailprotected ] will sit about these small things an appropriate wrench turn... Guns since he was 18 would n't glue on a flat surface and rub the crush washer can the... Of metal grease properly centers and indexes your barrel and then the muzzle brake installing a muzzle brake with a crush washer any kind of firearm each! Finally removing the muzzle unscrew it the installation installing a muzzle brake with a crush washer our muzzle device properly... None of the spring webwe install all breaks at the best online prices at eBay Hungarian-style! In 1/2 x 28 TPI for 223 up to date medical information and life saving.... Family with over 24 years of experience with the barrel, then screw in the desert where moisture is responsible. Of 20, and a maximum of 45 lbs cant use a -inch open-end.. Brake/Flash hider, and youre good to go likely what youll get when you purchase a upper! Not always the case or shims to install a muzzle device change is not responsible for any damage caused the! A bit of metal grease properly centers and indexes your barrel and then the device..., nuts, or lacquer thinner to clean the threads stronger if doesnt...
In this case, a muzzle brake cannot be installed on a barrel that does not have a threaded end.
We believer its possible, but from what weve seen, why wouldnt you want a Compensator that gives you the best of both worlds? Also, what about the finish? Peel washer act as spacers and can not be shifted to one side like a crush washer can. For the best experience on our site, be sure to turn on Javascript in your browser. We wont technically be installing a Flash Hider, but the BattleComp 1.5 Compensator. 5. If you need nuts or washers, place them on top of the barrel, then screw in the muzzle brake.

Place a hammer punch onto the roll pin and tap it out. We repeat DO NOT re-use the original crush washer. 5/8x24 Bergara rifle. 4. Its always confusing to choose the right direction of the crush washer. Crush washers are entirely appropriate for any open aperture muzzle device, such as the standard A2 birdcage flash hider. They tighten against each other and lock.

It will be as accurate as it was without one. Make sure to tune in later. Learn more about joining our Community as a Crew Leader.

All the ones I've installed so far have used crush washers. It also puts your mind at ease if you have OCD about these small things. It may not display this or other websites correctly. Id only remove it if it needs cleaning. Instead, it will properly cushion your muzzle brake now. Retcop Silver Patron 50.7k Location:SOUTHERN Illinois Posted February 27, 2019 (the added length and mass of a suppressor can compress one side of the spring under recoil/barrel flexing, causing a coaxial misalignment and in turn, baffle strikes. For VG6 muzzle devices the proper 12 oclock position is opposite of the laser engraving found on the muzzle device. I have years of experience with the carbines and never had an issue. There is a shim kit available that should take care of that for you.

Hopefully you found this guide useful. Crushwasher(Not the best from an engineering standpoint, but has proven reliability). (really, why?) I live in the desert where moisture is not a big problem, however I know I need to get it covered. A muzzle devices installation may necessitate specific tools, though this is not always the case. Display as a link instead, lbs., start with 15 and work up. Installing a muzzle brake is a simple process. Crush washers are cheap. Using a wrench over bare hands is always recommended. I wouldn't use a crush washer on a brake or suppressor mount. The installation steps are virtually the same and well get into detail on what the differences are between a Muzzle Brake, Flash Hider, Compensator and even a Flash Suppressor. ), the height of the crush washer wouldnt allow us to align the BattleComp properly. Once properly aligned and torqued, the BattleComp will need to be permanently affixed to bring the 14.5 barrel to the legal 16 length and avoid a $200 tax stamp to make an SBR (Short Barreled Rifle). - Includes new crush washer - 100% made in the U.S.A. - Lifetime Warranty Weight 3.6oz Weight 3.6 oz MPN MI-AR-MB1 Muzzle Device Type Muzzle Brake Threads 1/228 Caliber Midwest Industries Muzzle Brake 1/2x28 MI-ARMB1 from all vendors. Place a hammer punch onto the roll pin and tap it out. Remove the muzzle device and install shims The crush washer isnt technically a washer.

These can be used in place of either Crush Washers or Peel Washers if theres enough room (based on the muzzle device). Avoid using of crush You will need a vise, a basic series of wrenches, a jam nut, masking tape, and other items. Best Magnifier For Sig Romeo 5 [Finding The Juliet For Romeo], Best Mount For Aimpoint Pro [Aim For The Perfection], Best Trijicon Mro Mounts [Mount Without Wiggle Room], Best Scope Mounts For Sako 85 [Mount Fitted For A King], Best Sights For Winchester 94 [Get A Peep Sight Or A Scope. Features: Provides consistent torque level through entire rotation. Find many great new & used options and get the best deals for Shark Muzzle Brake 1/2" x 28 Thread .223 /w Crush Washer at the best online prices at eBay! Tapered side toward the receiver, concave side toward the muzzle. Tight fit to outer diameter of threads which helps center on the barrel. Szczinator $21.99. Thanks to the generosity of our supporting members and occasionally earning money from qualifying purchases as an Amazon Associate, (when you click our Amazon links) weve eliminated annoying ads and content. accelerated exhausted $19.99: You can buy the peel washers at most suppressor dealers. Heres what you need to do: Unload Your Rifle and Hold it Steady. Due to excess pressures and gasses associated with rifle calibers in short-barreled firearms, a barrel length restriction was implemented for many of our popular devices. 4.07K subscribers. Accu-Washer Muzzle Device Alignment System.

Yet, most muzzle devices will take the standard crush washer. It may not display this or other websites correctly.