Borka® bits are made of S2 tool steel and are known for exceptional toughness and resistance to breakage.  

Common Firearms Applications for Hex 5/64″

The 5/64-inch hex bit is a rugged, precision tool commonly found in AR-15 components, optic mounts, and modular pistol platforms. It's slightly larger than 1/16″, offering enhanced torque handling for parts subjected to recoil or operational stress.

1. AR-15 Grip Screws

• Application: Secures the pistol grip to the AR lower receiver.

• Platforms: Mil-Spec AR-15 and AR-10 builds; widely used across commercial lowers.

• Why 5/64″?: Allows for secure torque and easy removal without thread damage; threads often engage into the safety detent spring tunnel, so precision is important.

2. Gas Block Set Screws

• Application: Locks low-profile gas blocks onto the barrel (especially in free-floated handguard systems).

• Style: Most often dual set screws on the underside of the gas block.

• Brands: Used by Aero Precision, BCM, Faxon, Geissele, and others.

• Best Practice: Apply Rocksett or high-temp red Loctite and dimple the barrel for alignment.

3. Scope Rings and Mounts

• Application: Tightening ring caps or base-to-rail attachments on rifle scopes.

• Platforms: Bolt-action rifles, MSRs, and precision rigs.

• Brands: Common with Vortex, Warne, Leupold, Burris, and Midwest Industries.

• Why 5/64″?: Provides just enough bite for moderate torque (15–20 in-lbs) without stripping the screw or damaging the optic tube.

4. Pistol Optic Adapter Plates

• Application: Fastens adapter plates or MRDS optics to handgun slides, especially in:

  • CZ (e.g., P-10 Optics Ready)

  • Sig Sauer (e.g., P320 Pro Cut, X-Five Legion)

• Sights: Used with Leupold DPP, Shield RMS, Holosun, Trijicon, etc.

• Why this size?: Balances small profile with durability under recoil in handgun applications.