Technical specifications

According to the NATO Army Armaments Group the differences between the MIL-STD 1913 Picatinny rail and the STANAG 4694 are:

• A metric reference drawing.
• Additional new measurements and tolerances.
• Adjustments of some measurements.
• Reduction of straightness tolerances with approximately 50%.

Another notable change is the recommendation that while in the Picatinny rail system the V-angles are used for the alignment and reference of the accessory, NATO recommends using the top surface instead.
NATO tests have shown that the Picatinny rail system does not provide good repeatability. Using the top surface as a reference and alignment of the grabbers provided excellent repeatability.

The one piece free float handguard featuring an uninterrupted upper rail platform, 6061  aluminum construction and a superior hard coat anodized finish. Installation requires the removal and re-installation of the barrel nut , this requires the use of a barrel nut wrench. All rails are CNC machined to NATO NAR 4694 Specifications.

Technical Information

Quad Rail Hand guard Type: FREE FLOAT

• Rail type: 4 sides/NAR STANAG 4694
• Material: Anodized aluminum
• Type: AR15/M4 & VARIANT
• Length: 10.25inch
• Weight: 13.7 oz
  Tools Needed:
• Vise
• Hammer and Punch
• Barrel Nut and Barrel Wrench
• Receiver Action Block
  
  Installation Instructions:
  Ensure the firearm is unloaded and pointed in a safe direction. Remove the upper receiver from the lower. If there is a flash suppressor and front sight, these need to be removed next. Remove the old handguards. Using the barrel nut wrench remove the existing barrel nut. Place the barrel nut collar over the threaded portion that the barrel nut was removed from. Install the new barrel nut, after making sure the gas tube hole is correctly aligned, tighten the barrel nut down and install the new handguard using the included Allen head cap screws.  Many more video installation instruction at youtube.com. Type in keyword "Free Float Quad Rail Installation".