Andro Corp Bolt Carrier Group Features The Andro Corp Industries Bolt Carrier Group is machined from steel and built to the full auto bolt carrier pattern used in select-fire AR15 and M16 platform rifles. That heavier carrier geometry is designed to handle the added cyclic demands of full auto fire while remaining fully compatible with semi-auto AR15 lowers. The black nitride finish adds a hard low-friction surface that improves heat resistance and reduces the need for heavy lubrication during sustained firing. At 7.5 inches overall the carrier meets Mil-Spec length requirements for standard AR15/M16 upper receivers. Because it is built for AR15 and M16 platform rifles this BCG drops into most Mil-Spec upper receivers without modification simplifying installation for builders and armorers. The steel construction stands up to repeated cycling and the wear that comes with high round counts far better than lighter alloy alternatives. Its black nitride coating also makes cleaning easier since carbon and fouling wipe away more readily than on untreated steel. For a rugged full auto rated bolt carrier group built for AR15/M16 platform rifles the Andro Corp Industries BCG is available for sale at GrabAGun. Andro Corp Bolt Carrier Group Specifications Manufacturer: Andro Corp Compatible Hosts: AR15 / M16 Color: Black Material: Steel Bolt Type: Full Auto Finish: Nitride Length: 7.5 Available At: GrabAGun