Note: Image may not be an exact representation of the actual item. Please read the complete description before purchasing.

CMMG AR-15 Complete Semi Auto Lower Assembly Mil-Spec Buffer Tube 6 Position Stock Black Finish 55CA360

CMMG, Inc.
| Tell a Friend
Can we ship this to you?
Typically ships within 1 to 2 business days when a valid FFL is received
  • All firearm sales are final. NO RETURNS.
  • Return to manufacturer for warranty service.
  • Actual buyer must pickup from FFL dealer who will conduct the background check. Learn more
  • Firearm transfer must be the actual transferee/buyer. Click here to see BATFE form "Transaction Record Part 1".
  • Firearms are only available for purchase online.
A $10 handling fee will be charged per order. No additional charge for multiple firearms on an order.
The CMMG AR-15 Mk4 Complete Lower Group with MK4 Collapsible Butt Stock is an excellent starting point for your standard AR-15 build. This will work with most standard AR-15 calibers like the 9mm Luger, .40 S&W, 5.56 NATO, .223 Remington, .300 AAC Blackout etc. Starting with a high quality component like the CMMG Mk4 Complete Lower Group with MK4 Collapsible Butt Stock gives you assurance of quality in form and function. Don't use sub par parts from some unknown manufacturer, go with a name you can trust, go with a CMMG AR-15 Mk4 Complete Lower Group with MK4 Collapsible Butt Stock.

Specifications and Features:
CMMG AR-15 Mk4 Complete Lower Group with MK4 Collapsible Butt Stock
6 Position Mil-Spec Extension
Forged 7075-T6 Aluminum
Hard Anodized Black
Single Stage Mil-Spec Trigger
A2 Pistol Grip
Standard AR-15 Safety Selector
Standard Carbine Spring and Standard Weight Carbine Buffer
Standard takedown/pivot pin holes and .155" hammer/trigger pin holes

9mm Luger, .40 S&W, .45 ACP, 10mm Auto, 5.7x28mm, 5.56 NATO, .223 Remington, .300 AAC Blackout, .24 Ruger, 5.45x39mm, .300 Whisper, 6.5mm Grendel, 6.8 Remington SPC II, .458 SOCOM, and .50 Beowulf


Item#: 2-CMMG55CA360
Buying a Firearm Online is Easy!
  • Add your selected firearm(s) to your shopping cart and check out.
  • Select a local Federal Firearms Licensed (FFL) Dealer that will accept the firearm and complete the transfer. Find a FFL Dealer HERE.
  • If you choose an FFL Dealer that is not on our preferred list, you or your FFL Dealer will be required to fax or email us a signed copy of the Federal Firearms License referencing your Cheaper Than Dirt! order number.
  • Pick up your firearm from the FFL Dealer, who will need to do a background check. Transfer fees may apply.
Buying Firearms on the Internet

Federal law requires firearms to be shipped to FFL Dealers. For an individual to receive a firearm from Cheaper Than Dirt! it must be shipped to an FFL Dealer in your state.

Locating a Federal-Firearm License Dealer (FFL) in Your Area

There are thousands of FFL Dealers in the United States. You may choose an FFL Dealer from our preferred listing or you may find a dealer in your area. To find a list of FFL Dealers in your area area CLICK HERE. If you choose a dealer that is not on our preferred list, either you or the FFL Dealer will be required to submit a copy of the Federal Firearms License referencing your Cheaper Than Dirt! order number. The FFL Dealer will usually charge a fee to conduct the transfer. There are duties that the FFL Dealer is required to do during the process which include a background check. Remember, the FFL Dealer is doing you a favor and the process takes time to complete. Fees can vary so check with the FFL Dealer ahead of time to request a quote on the fees associated with your firearm transfer. The FFL Dealer is in business to make a profit and your internet purchase may be viewed as competition to their retail business. If you feel the fees are too high, you can search for another FFL Dealer.

Completing the Transaction

Once you place the firearm in your cart and checkout you will receive a confirmation email that has your order number and further instructions. We will verify the FFL license and also make the FFL Dealer aware that an order from Cheaper Than Dirt! will soon be arriving for you. Most orders are processed within 2-3 business days from the time we receive and verify the FFL Dealers information. Once shipped, your firearm will arrive at the FFL Dealer within 3-7 days business days. The FFL Dealer will begin processing the shipment. It may be an additional day or so before the FFL Dealer is ready to conduct the transfer of the firearm to you. Call the FFL Dealer and set an appointment to confirm that the firearm is ready to be transferred.

Please note! All Firearm Sales are Final

It is important to thoroughly inspect your firearm before completion of the transfer. Once the firearm is transferred into your name, Cheaper Than Dirt! will not accept a return or exchange under any circumstance. If a defect is discovered after completing the transfer, you must contact the manufacturer directly for repair or replacement.