These AR15 anti walk / anti rotation hammer and trigger pins are what you need to keep your receiver from excessive wear and tear. Keeping the hammer and trigger pins from rotating is especially important when shooting full auto or with pistol caliber builds, such as 9mm AR15's.
Rise Armament Blitz Elite Performance AR-15 Trigger w/ Anti-Walk
KNS Precision .154 Non-Rotate Trigger / Hammer Pin MOD ST
Stag Arms AR-15 Stag 15 Anti-Rotation Trigger/Hammer Pin Set
AR-15 Non-Rotational Anti-Walk pins-PINS
JP Enterprises AR-15 Oversize Antiwalk Pins - .156
Guntec USA AR-15 Complete Anti-Rotation Trigger/Hammer Pin Set
AR-15 Complete Anti-Rotation Trigger/Hammer Pin Set (Anodized
Titanium AR Anti-Walk Hammer & Trigger Pin Set
AR-10 .308 EZ PULL EXTENDED TAKEDOWN PIVOT PIN SET AR10 EASY PULL
AR-15 / AR-10 BURNT BRONZE CERAKOTE Anti Walk Hammer Trigger Pins