NA5 - HK 416A5 Style Adjustable Gas Block
NA5 - HK 416A5 Style Adjustable Gas Block
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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
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No issues with installation. Was easy to just, just took a little time to try the different jets. You need to make a version for the MR762.
Great gas block. The fit and finish were exemplary, and the knob was nice and movable, making it easy to turn with the tip of a bullet from various angles. Gassing on a brand new MR556A1 barrel was perfect with the factory-installed 1mm vent screw, giving 1:30-2:30 ejection on N and 3:30-4:30 ejection on S with a B&T SRBS installed. Wonderful product and a great price for everything you get!
Let customers speak for us
from 57 reviewsA hard to find item which you had in stock. Order placed in the am and shipped the same day. Quality parts and outstanding service!
Shipped same day and was exactly as described! Yall are awesome! Cant wait to buy more stuff!
Heavy duty and well machined.
This company is great! Marvin is an artist, orders sometimes will take a while but rest assured when you do get it, it will be perfect, so if youre a potential customer, be patient. It will be done
I enjoyed all the products so far. I plan to purchase more products in the future, keep up the good work!
I used this tool to build a Nefarious Arms A3 IAR barrel on an MR556 upper, and it was absolutely perfect for the job. It easily held under the required torque specs with zero barrel shift. More importantly, it eliminated any worry about shearing off the index pin, ensuring near-perfect timing after installation.Before this, I attempted to use a Midwest Industries Reaction Rod but found way too much play. The MR556 platform demands tight tolerances, and a generic reaction rod simply doesn't offer the precision needed. Because this tool is made specifically for these barrels, the fit is exact. If you are doing an MR556 build, this is the tool you need.
Nothing but the best.
Wow! I'm so glad I was able to grab the last SOCOM profile 14.5 A5 barrel available for now. IMO the fit and the finish is top notch and can't be matched.
I shot nice thight groups out to 100m... so, I can't complain. Looking back, I wish, I could have gotten at least one more barrel for a future A5 project.
Alan Taylor
Dallas, Texas
Very high quality barrel. I would consider this to be as good if not better than the hk made barrels. The chrome lining is excellent and the overall fit and finish is top class. Very smooth shooting would definitely recommend if you are wanting to build a clone or just looking for a high quality cold hammer forged chrome line barrel.
Just got it last Friday so I haven't shot it yet. I purchased the barrel and had Marvin install it on an MR556A4 upper. The work looks really good (no little nicks or anything), the barrel itself is well-made and it's nice seeing a chrome-lined barrel on an HK MR carbine! Would definitely recommend Marvin's work as well as NA for offering us "civvies" a mil-spec barrel. Kudos!
P.S.- Holly answers the phones there and she was very helpful and polite. You all have a solid employee!