Rankin Industries SP4 Coated Bolt Carrier Group Mil Spec M-16 AR-15 5.56

Rankin Industries SP4 coated bolt carrier group has a new SP4 hybrid DLC coating that is the result of years of development.  SP4 combines super high hardness of around 3000 HV with flexibility to remain tough without being brittle.  This is a drastic improvement over common PVD and DLC type thin film coatings.  SP4 reduces friction and improves wear resistance for metal components and provides a longer life span for the bolt carrier group.  This bolt carrier group requires minimal maintenance.  You simply use a dry cloth to wipe it down when you are ready to clean it.  The carbon comes right off and finds it very difficult to stick to the SP4 coating.  The most impressive feature of this bolt carrier group is that it does not need any lubrication.  Through all the testing that has been done, it runs best with no lubrication at all.

The SP4 has been tested in the mountains of Alaska at -44 degrees and in the hot climates of Iraq and Afghanistan with no lubrication.  The SP4 has passed the ASTM 85 (Annex 1) Salt Fog test.  This means that even in high humidity and even in salt water, this bolt carrier group is tough.  It simply provides the hardest and lowest friction coefficient available on the market today.  It does all of these things while being the most flexible coating as well.  SP4 coating is in use in race car engines and transmissions and has a great reputation in NHRA and NASCAR groups.

Full Auto or Semi Auto

Rankin Industries SP4 Coated Bolt Carrier Group Mil Spec M-16 AR-15 5.56 full auto version for use in semi-auto rifles and pistols.  This is for full auto or semi auto AR15, M16, and M4 rifles and pistols.   machined from Mil-Spec 8620 aircraft quality steel with shrouded firing pin and Mil-Spec chrome lined interior. The SP4 coated bolt carrier includes the proper chrome lined and heat treated gas key. The gas key is secured to the carrier with Grade 8 fasteners and properly staked per Mil-Specs. This ensures a strong staking and proper gas system functioning. The bolt assembly is CNC machined from Mil-Spec Carpenter No. 158® steel and shot peened for increased strength per Mil-Spec.  The SP4 Coated bolt carrier includes tool steel extractor with spring and viton O-ring.

Rankin Industries SP4 Coated Bolt Carrier Group Mil Spec M-16 AR-15 5.56 is designed to reduce the friction coefficient.   This lowers the operating temperatures and increases the overall performance and the Bolt Carrier Group’s life.

Backed by a lifetime guarantee, you can be confident that this coated BCG will increase lubricity and wear resistance.  This bolt carrier will provide a smoother recoil, improved consistency, faster cyclic rate and reduce carbon fouling.

SP4 Coating is on the following parts: Bolt Carrier, Carrier Key, Cam Pin, Firing Pin, Bolt, Extractor, Gas Rings.

HPT (High Pressure Tested) and MPI (Magnetic Particle Inspected).

Rankin Industries Complete Mil-Spec M-16 Bolt Carrier with Bolt Assembly HPT/MPI Tested:

• Mil-Spec BCG Machined from 8620 Aircraft Quality Steel and heat treated to 60-61 RC
• Mil-Spec Chrome Lined Carrier Interior
• Mil- Spec Chrome Lined Gas Key from 4130 Steel
• Key Staked with Grade 8 Screws and torqued to 58 inch pounds per Mil Spec.
• Mil-Spec Carpenter 158® Bolt w/ Spring and Ejector
• Tool Steel Extractor w/ Spring and viton O-ring
• Mil-Spec Firing Pin
• Mil-Spec Cam Pin
• Full Auto Carrier is Backward compatible with all semi-auto rifles
• Full Auto M-16 5.56 BCG Weight – 11.40 oz.
• SP4 is a Thin Film that has a thickness between 2 and 3 microns
• Hardness is 3000 on the Vickers scale
• Friction Coefficient is an incredible  .02
• SP4 is also the most flexible coating on the market.
• SP4 is #1 in Hardness; #1 in Low Coefficient of Friction; #1 in Flexibility and Elasticity