SUREFIRE INSTITUTE AR-15 COMPLETE M/4 LOWER RECEIVER

Combined with a patent pending fire control system, the proprietary lightweight polymer construction of the SFI-15 lower receiver provides a superior strength-to-weight ratio.

The SFI-15 uses the following metal parts:

• Takedown pin detents and springs
• Hammer/Trigger pins and springs
• Bolt catch, spring, & roll pin
• Magazine catch spring
• Pistol grip screw
• Buffer, buffer spring
• Buffer detent and spring
• Castle nut
• Receiver end plate

All other parts are constructed using polymer