CMMG Inc Receiver Extension and Stock Kit Carbine AR-15. Features of CMMG Inc Coll Butt Stock Kit 6 Position: CMMG 6 Pos Receiver Extension Carbine Buffer Assembly Carbine Action Spring 6 Position Butt stock Assembly Package Contents: CMMG Inc Coll Butt Stock Kit 6 Position Specifications for CMMG Inc Coll Butt Stock Kit 6 Position: Manufacturer: CMMG Gun Model: AR-15 Stock/Brace Material: Polymer Aluminum Gun Type: Rifle Weight: 2 lb Length: 15 in Buffer Tube Size: Mil-Spec Fabric/Material: Alum/Poly Package Contents: CMMG Inc Coll Butt Stock Kit 6 Position What firearm models does the manufacturer say CMMG Inc Coll Butt Stock Kit 6 Position is compatible with? The manufacturer says that CMMG Inc Coll Butt Stock Kit 6 Position is compatible with AR-15CMMG Inc Coll Butt Stock Kit 6 Position - 55CA634