Dark mode is

Product Unavailable

Unfortunately, the following product is currently unavailable through Rainier Arms.

SIG SAUER MCX 300BLK Suppressed Complete Upper - 16.8"

Complete Upper


This is a new OEM Sig Sauer MCX Conversion Kit that includes an integrally suppressed MCX upper receiver, adapters to convert the lower receiver to accept the MCX upper receiver, and a Sig Sauer two-stage trigger. The trigger installation is required to ensure proper operation of the MCX upper receiver. Using your existing trigger is not recommended and may lead to malfunction.

The suppressor is pinned and welded meaning that the overall length is just over 16". Putting this on your rifle will not make it an SBR.


  • Caliber .300 Blackout
  • Manufacturer Sig Sauer
  • Sights (detailed) None
  • Frame Finish Black
  • Barrel Length (in) 16.8 in OAL
  • Accessory Rail Not Applicable

FFL and SOT Required Before Shipping. 

Please have your dealer email their license to [email protected] or they can also fax it in. Please give us a few days to process the information

More Information
Product Type Complete Upper
Manufacturer Sig Sauer
Google Customer Reviews Google Customer Reviews