Sig Sauer MCX Upper Receiver - 16" 5.56mm NATO

This is a new OEM Sig Sauer MCX Upper Receiver to convert your MCX from another caliber to 5.56mm NATO or upgrade your standard AR15 lower receiver. This kit includes the buffer tube eliminator which is necessary for the conversion. This will allow you to install adapaters to use your existing M4 style tube and stock or you can purchase one of the OEM SIG side folding MCX stocks.