Welcome to Red Dot Arms - Red Dot Arms, Inc. is a multi-faceted business dedicated to the education of individuals on the proper use and care of firearms. Red Dot Arms also sell a full line of firearms and ammunition. Whether you are a novice or marksman or somewhere in the middle, Red Dot Arms NRA certified instructors and knowledgeable sales staff can be your resource for all your firearm related questions and needs.

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CMMG MK4 S 5.56 MM 18", Black Zoom

CMMG MK4 S 5.56 MM 18", Black

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CMMG MK4 S 5.56 MM 18

The CMMG MK4 S 5.56 MM 18", Black includes (1) 30 round magazine, A2 pistol grip, and no sights.

Availability: Out of stock


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Product Description


This Mk4 S is the perfect rifle for the tree stand or target range. The Mk4 S utilizes an 18″ 416 stainless steel medium taper barrel chambered in 5.56x45mm NATO and CMMG’s RKM14 KeyMod hand guard. The rifle’s KeyMod hand guard is ready to accept any number of the sling mounts, bi-pods and other KeyMod compatible accessories making the ultimate in versatility and modularity. Each rifle includes a magazine and CMMG’s lifetime quality guarantee.


  • Caliber: 5.56 MM
  • Capacity: 30
  • Magazines: 1
  • Barrel Length: 18"
  • Finish: Black bead blasted finish
  • Action: Semi-Automatic
  • 1:7 twist, medium taper, 416SS
  • Muzzle: A2 comp., threaded 1/2-28
  • Hand Guard: CMMG RKM14 KeyMod hand guard
  • Furniture: A2 pistol grip, M4 butt stock with 6-pos mil-spec receiver extension
  • Receivers: Forged 7075-T6 AL M4 type upper, AR15 type lower
  • Trigger: Single stage mil-spec style trigger
  • Weight: 6.7 lbs (unloaded)
  • Length: 34” (stock collapsed)
  • Gas Port Location: Rifle
CMMG MK4 S 5.56 MM 18 CMMG MK4 S 5.56 MM 18

Additional Information

Additional Information

SKU 55A66E1
UPC 0815835015453
Manufacturer CMMG, Inc
Type Semi-Auto
Action Type No
Barrel Length No
capacity No
Finish No
Overall Length No
Safety No
Sight No
Grips No
Number of Mags No
Price $989.99
Available for In-Store Pickup Yes
Bin Number No


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Firearms Policy

How to Buy a Firearm or Ammunition

Federal firearms laws prevent the sale of a weapon from Red Dot Arms, LLC. directly to an individual in another state (we are located in Illinois). We must ship your firearm directly to an FFL Dealer near you. The steps to follow are:

  1. Order your firearm online using our secure shopping cart. If you know the FFL dealer you are going to use at time of order placement (not a requirement) enter his name and address into the 'Ship To' field.
  2. Find an FFL dealer near you that will accept the transfer of the firearm for you. Most sporting goods stores and pawn shops will provide this service for a small fee. Also, gun clubs, shooting ranges, etc. may provide this service to you. If you don't know which FFL dealer to use in your area, put a comment in your order and we will help you locate one near you. We have access to a large list of dealers in the USA that will gladly handle a transfer for you. Most dealers charge around $25 for a transfer. You must confirm the transfer with your local FFL dealer in advance.
  3. Next, have the dealer send us a copy of his signed license if we don't already have it on file. To check whether a license is on file, contact us. Please Note: It is now legal for us to accept a faxed or e-mailed copy of your dealers license! 
  4. Make sure the dealer knows the firearm is coming from Red Dot Arms. If you used a dealer that we already have on file, call him to let him know that a gun for you is on the way.
  5. We will send you an email when the firearm ships, which will include a tracking number.

Backorder Policy

Backorder Policy

If an item is available for Backorder, you can still ADD it  to your Cart, and place the order. Typically, items on Backorder require between 6-10 Weeks before fullfillment. If you have multiple products in your Cart during checkout, items that are IN STOCK, will ship first and your Backordered products will ship seperately. 

Red Dot Arms will notify you via email when your Backordered item is fullfilled. At anytime, you can also login to your Account for shipping status. 

Why Backorder? 

Due to the nature of the current market landscape, certain items are in high demand. By placing a Backorder, it ensures that you will be at the top of the list when HOT items become available on the Red Dot Store. 

Will My Credit Card Be Charged for a Backorder?

No. Your credit card and the purchase amount will only be charged at the time of order fullfillment.