D.F. Maisey Gunsmithing Services logo
D.F. Maisey Muzzle Brakes

Gas Blocks


 (Note: Due to NZ firearms law changes in 2019, these items are now classed as parts for prohibited weapons, and can only be supplied to P-endorsed license holders, subject to availability.)



Designed and CNC machined in-house, this solid steel adjustable gas block features up to 32 click-stop settings, and simple one-tool operation. It is essentially a slimmed-down and revised version of our earlier AGB1 model gas block, and is ideally suited to AR type rifles which are fitted with one of the newer style slim-line free-float tube forends which may require the gas block to be housed inside of the forend piece. This adjustable gas block may be used in conjunction with a suppressor or other muzzle attachment to correctly regulate the gas impulse for smoother cycling, reduced recoil and gas spit from the action area, and to eliminate over-vigorous extraction which can lead to case damage or parts breaking prematurely. Click here for PDF info sheet of AGB2 specs.
Registered Design (Design Patent): NZ422350
(International Patents Pending)

NZ$180+gst (NZ$207.00 Incl GST)

Contact us by email or phone to check on current availability or to place an order.

ADJUSTABLE GAS BLOCK FOR AR15 TYPE RIFLES – model AGB3 (slimline – for 0.625″ barrels)


The AGB3 is our new adjustable gas block for AR15 rifles with 0.625” diameter barrel journal. This new slimmed-down model is designed to fit inside the new style long/slim forend tubes of 1.2” internal diameter (31mm) or larger, or outside of the forend assembly if required. Works well with the FAXON ultralite barrels, or GI .625” barrels. The AGB3 block is slimmer and shallower than our AGB2, and the design has been optimised for the 0.625” barrels.
Like our original AGB1 and AGB2 models, this unique design allows the shooter to easily and quickly adjust the standard AR gas system to restrict or prevent ‘over-gassing’ effects which may cause premature parts breakage, or other problems like excessive gas blowback into the shooters eyes, particularly when these rifles are used in conjunction with a suppressor.  This unit is designed for best strength and durability, and does not have any flimsy or weak screw systems as found on some imported products. Aluminium is deliberately NOT used for the gas block body. Larger, stronger cap screws are used to avoid stripping the hex-slots, and more ergonomic and novel angled main-screw design for ease of adjustment – all from the front of the gas block. This gas-restriction system achieves slightly higher bullet velocity than ‘bleed-off’ gas block systems, and is quieter with a suppressor.

(Note that some ‘bleed-off system’ claimed benefits of better erosion resistance compared with common ‘restriction’ type gas blocks, etc. are overstated and (in my opinion) misleading.) In terms of durability, ease of use and reliability, the AGB1, AGB2, and the new AGB3 gas blocks are the equal or better of any other (direct impingement) AR gas block system on the market anywhere in the world.

100% designed and made in NZ.

  • Suits barrel journal diameter: 0.625”
  • Solid steel body, black (gas) nitrided finish for surface hardness and rust resistance, including holes and threads
  • Stainless steel (316 marine grade) main adjustment screw (extremely high erosion resistance – better than the barrel steel itself!
  • Stronger detent/screw design than most other Adj. gas-blocks.)
  • Detent ball and spring system located at front end of block to avoid excessive carbon fouling.
  • Simple one hand/tool operation from front of gas block
  • Allen/hex keys and fitting instructions all included.
  • Clamps securely to barrel with 2x grub screws on underside 
  • Flat sides of gas block body make fitting, alignment, and gas tube installation easier. Close tolerances for snug fit with other parts.
  • Unique/novel offset angled adjustment screw design permits 8 clicks per revolution (32 max), from fully-closed (bolt remains in battery) to fully-open.
  • Weight: 77 grams (2.7oz). Block length: 1.250” (31.75mm) 
  • Low profile design
  • NZ-made product, and is a Registered Design (NZ422350).  www.gunsmith.co.nz

NZ$180+gst (NZ$207.00 Incl GST)

Contact us by email or phone to check on current availability or to place an order.

Hunter and mountains landscape Hunter and mountains landscape Hunter and mountains landscape