Luth-AR Bolt Assy AR - Assembled Black. 223 Bolt Assembly AR Specifications for Luth-AR AR Bolt Assy - Assembled: Manufacturer: Luth-AR Color: Black Fabric/Material: 4140 Chrome Moly Caliber: .223 Remington Gun Make: AR Platform Gun Model: AR-15 Additional Features: Assembled Features of Luth-AR AR Bolt Assy - Assembled Bolt: Due to supply chain issues material for the bolt may vary. Mil-Spec heat treat Manganese Phosphate Extractor: 4140 Chrome Moly Machined from bar-stock Mil-Spec heat treat Manganese Phosphate Package Contents: Luth-AR AR Bolt Assy - Assembled What firearm models does the manufacturer say Luth-AR AR Bolt Assy - Assembled is compatible with? The manufacturer suggests that Luth-AR AR Bolt Assy - Assembled is compatible with AR-15Luth-AR BT-09: Bolt Assy AR - Assembled Black