NA5 - HK 416A5 Style Adjustable Gas Block

The NA5 gas block allows conversion of the MR556 / MR223 to the new A5 style rifle. The block itself is a bit longer than the factory A5 gas block to cover the front cross pin hole of the MR barrels. The block is held in place by the rear pin only, just like the factory HK 416A5. The indexing tab on the back of the block is 3mm to fit the MR556 / MR223 width barrels and will be a direct fit.   

• Hardened Steel
• Titanium Leaf Spring
• Black Melonite Finish 
• 2-Position ("N" for Normal, "S" for Suppressed) 
• 6 Gas Vent Adjustment Screw Sizes 
  

Compatible with: 

• HK 416
• MR556 / MR223

The gas block has a vent on the ejection port side that can be exposed ("S" mode) or covered ("N" mode) by manipulation of the selector cap. The "S" mode is for use of a silencer. The "N" mode is for normal "non-suppressed" use. 

The gas block has a disassembly notch marked at the 12 o'clock position. The cap has a corresponding notch to indicate the position where it can be removed from the gas block for inspection and cleaning. The index spring will need to be depressed to aid in the removal of the cap for cleaning and maintenance. 

Note: Not intended for use with barrels under 11", due to interference between the adjustment knob/cap and muzzle device or suppressor. May require barrel/gas port modification. Recommended gas port size for 11" barrels is 1.0mm "pre-installed in gas block". 

Content List:

• NA5 Adjustable Gas Block Assembly 
• 0.7mm Gas Regulator Screw (Yellow)
• 0.8mm Gas Regulator Screw (Green)
• 0.9mm Gas Regulator Screw (Blue)
• 1.0mm Gas Regulator Screw (Gray, Pre-Installed) 
• 1.6mm Gas Regulator Screw (Silver)
• Non-Vented Gas Regulator Screw (Black)
• 3/32" Hex Driver (5")
• 3Nm Torque Wrench
• 5mm x 18mm Spring Roll Pin 
• Anti-Seize

NA5 Adjustable Gas Bock Instructions PDF