Alex Pro Firearms Ar15 Sp4 Ltwt Bolt Carrier Group

Alex Pro Firearms (APF) is proud to introduce BCGs featuring SP4 a new hybrid DLC (Diamond Like Carbon) coating that is the result of over a year in development. SP4 combines high hardness (2500-3500 HV) with ductility to remain tough without exhibiting brittleness vs common PVD/DLC type thin film coatings. SP4 reduces friction and improves wear resistance for metal components which provides a longer life span and requires minimal maintenance with little to no lubrication. It has been tested to -44 degrees F in the mountains of Alaska and has been tested in the both Iraq and Afghanistan with no lubrication which is a huge advantage in desert environments and extreme cold. SP4 has passed the ASTM 85 (Annex 1) Salt Fog test and provides the best hardness/lowest friction co-efficient while maintaining the ability to
move
with the metal it is protecting. Includes a hand polished bolt carrier with a chrome lined bore and staked gas key bolt with gas rings firing pin cam pin and firing pin retaining pin. - The APF BCG is machined to mil spec standards. - BOLT: - Carptener 158 - Shot Peened - Heat Treated - SP4 Coating - CARRIER: - SAE 8620 - Heat Treated - SP4 Coating - AR-15 - EXTRACTOR: - CNC machined - Shot Peened - Heat Treated - SP4 Coating - FIRING PIN: - Swiss machined - Heat Treated - Precision ground - SP4 Coating - GAS KEY - CNC machined - Heat Treated - Chrome Lined - Torqued and Staked to Carrier Mil Spec. - SP4 Coating - CAM PIN: - Swiss machined - Heat Treated - SP4 Coating