Sharps Rifle Company Xtreme Performance Bolt Nickel Boron. These Bolt Carrier Groups are machined from strong S7 tool steel tempered with a special Sharps Rifle Company heat treating process for superior durability and offers excellent corrosion resistance with an NP3 electroless nickel-based finish. The SRC Steel Relia Bolt works with all .223 and 5.56 variant part groups and can be installed quickly and easily with no tools. Choose the Sharps Rifle Company .223/5.56 Relia-Bolt for a bolt guaranteed to perform under pressure Specifications for Sharps Rifle Company Xtreme Performance Bolt: Manufacturer: Sharps Rifle Company Fabric/Material: S7 Tool Steel Caliber: 5.56x45mm NATO .223 Remington Condition: New Features of Sharps Rifle Company Xtreme Performance Bolt The Relia-Bolt is machined from S7 tool steel and tempered with SRCs proprietary heat-treating process significantly increasing strength when compared to MilSpec Carpenter 158. S7 provides a 75percent increase in tensile strength and nearly 60percent improvement in yield strength. Every Relia-Bolt is coated with Nib-X (Nickel Boron) an electroless nickel-based finish. This process co-deposits sub-micron particles of PTFE (polytetrafluoroethylene) commonly known as Teflon for self-lubricating corrosion resistance. Package Contents: Sharps Rifle Company Xtreme Performance Bolt Sharps Rifle Company RELIABOLTN: Xtreme Performance Bolt Nickel Boron