KWA Air Nozzle Alternatives: Redux

Updated 7/22/21:

Since originally publishing the KWA Air Nozzle Alternatives post back in July of 2014, I’ve been experimenting significantly with using different air nozzles. As with a lot of things in Airsoft, times change, things change, and nothing stays static forever. Accordingly, it it time to revisit that article and provide some much needed updates.

I’ve now arrived at a “set” of what I would consider to be the optimal replacement air nozzle choices for the current and older generation KWA rifles. The results of which are based upon installing literal hundreds of each type now, and finding consistent uniform and satisfactory results across the board.

The factory KWA air nozzle is a solid metal design not likely to break anytime soon. That being said, it is lacking an o-ring and is often the cause of major compression loss (low FPS) in the system. The approximate length is 21.11mm with a +/- 0.02mm length deviance measured across 50 samples. As near as I have been able to discern, the design has not changed between the G2X era rifles and the newer G3X

G2X Era Rifles – VFC 21.11mm Ver. 2 Nozzle

These are the old workhorses still plowing your local Airsoft field. I’m always amazed at how much abuse and mileage some of these guns get and still keep on ticking.

This series is comprised of the following G2X based models:

• KM4 SR7 / SR10 / SR12 / KM4A1
• CQR MOD 1 / MOD 2
• KM16
• KR12

The notable difference between rifles of this era and the more current iterations is that these guns have a two-piece hop up chamber design. While largely obsolete in light of current developments, it’s still a serviceable system and will turn in good accuracy if you do your part. Additionally, the tappet plate design is based on the more conventional “TM spec”. The sector gear sports a simple round style delayer chip.

Owing to this internal configuration, the best nozzle I have found thus far for the G2X series guns is the VFC Ver. 2 air nozzle. The approximate length of this nozzle is incidentally also 21.11mm.

It should be noted that using any nozzle longer than this may result in feeding issues.

G3X Era Rifles – Retro Arms 21.4mm Ver. 2 Nozzle

This generation of AEG 2.5 (variable FPS) and 3.0 (recoil) KWA rifles is comprised of the following models:

The tappet plate design is changed significantly from the old. The latest version of this gearset also has a new style of delayer chip, which resembles more of an ovoid teardrop shape. This series of AEG’s has also moved to a one-piece rotary hop up chamber. Despite using the same length air nozzle as found in the older G2X guns, the combined design of the tappet / sector / hop up lends itself exceptionally well to using a longer nozzle than the factory length.

For all of these guns, the best nozzle I have found to date is the Retro Arms CNC 21.44mm air nozzle.

In conjunction with some other compression fixes, obtaining highly consistent FPS is very much possible with this nozzle, as you can see from a customers CQB setup gun here:

In the past, I have also used Guarder, Raptors RTV and some others with good success – albeit not entirely perfect. The critical thing to note is that the design of the hop up chamber is not accepting of nozzles with a ‘fat’ cross-section, such as SHS; they simply will not fully seat. As the Retro Arms nozzle has a uniform shape throughout its length, it will not encounter this issue.

AEG 2.5+ and 3.0+ Series

With the introduction of the Tekken TK.45 series rifles, KWA has also made some design updates to the gearbox: chiefly the ability to use conventional Ver. 2 drop-in MOSFET triggers, such as the Gate TITAN. While bearing mostly the same naming nomenclature as the AEG 2.5 / 3.0 series, the chief distinction will be the “+” designation, which indicates these AEG’s do not feature the last round cutoff and have the TITAN compatible gearboxes.

This is the current generation of AEG 2.5+ (variable FPS, no cutoff) and 3.0+ (recoil, no cutoff) KWA rifles and is comprised of the following models:

Another new design feature currently specific to the AEG 2.5+ / 3.0+ series is the updated tappet plate and air nozzle. The nozzle is a polymer unit with an interesting o-ring design and a small notched end. The nozzle itself is also uniquely designed to slot into the tappet plate and measures out shorter due to the magazine placement on this gun series. The approximate length of the nozzle is 20.80mm.

As it stands, there is currently no aftermarket nozzle that will fit with this tappet plate. Part of this is due to the tappet plate being an entirely proprietary fit for the new nozzle design. That being said, I have found that better compression can be achieved by swapping the o-ring out with a slightly thicker type, such as that found on SHS nozzles

A superior alternative is to replace the existing tappet plate with the version as found on the standard RM4/VM4 series. Incidentally, the Retro Arms 21.40mm nozzle is once again the best choice here.

It remains to be seen whether the new tappet plate and nozzle design will be transferring over to future models, such as the upcoming KO:EVE series or even replacing the variant as found in the older AEG 2.5 / 3.0 series.

One issue I have seen crop up with this new nozzle design is that it will tend to crack along the mold seam at the 6 0’clock position. This will often be a hairline crack and not always readily visible, but will become a source of FPS loss.

A Note on MAXX CNC Chambers

It is possible to install the MAXX ME CNC rotary chamber in various KWA AEG 2.5 / 3.0 and AEG 2.5+ / 3.0+ models. More specifically, the ME “Sport” model is a direct drop-in fit and requires no modifications to the receivers or gearbox. The ME “Pro” will require modification of either the BB release latch or the gearbox due to the latch impacting the underside of the gearbox and not being able to full open.

Presently, MAXX ME chambers are compatible with the following models:

When using a MAXX chamber, you will need to use a different air nozzle than the aforementioned Retro Arms option. In this case, the MAXX 21.25mm nozzle works best.

And as previously mentioned, for the AEG 2.5+ / 3.0+ series, you will be best served by installing the older generation tappet plate so you can use the MAXX air nozzle. Absent that, you can use the existing design if you file down the ridge on top of the polymer nozzle.

There are some important considerations should you wish to utilize the MAXX chambers. I cover some issues with magazine compatibility here.

A Note on Nozzle O-Rings

Occasionally, you may find that the o-ring on either the VFC or Retro Arms nozzle is not providing a 100% seal with your cylinder head – whether it is the OEM KWA head or an aftermarket head, such as Lonex. This can be due to wear on the nozzle shaft or simply a matter of differing specs. Fortunately, the fix for this is very simple and that is to replace the o-ring with an SHS air nozzle o-ring. These o-rings are a little thicker than the majority of nozzle o-rings out there and are available for purchase in a 6-pack. They can also be harvested from SHS nozzles if need be too.

Alternatively, McMaster-Carr sells a chemical-resistant Viton Fluoroelastomer o-ring of the correct size in larger packs. Item #: 9263K285

The approximate size is 5mm X 1mm.

A Note on Compression

Replacing the air nozzle is but one facet of tuning the compression system in your gun. While critical gains can be achieved by replacing the air nozzle, it is only as strong as its weakest link. The other important areas you should be examining are the piston head and cylinder head compression. Another highly important area that is often overlooked is the hop up bucking to nozzle interface.

I have used and tested these aftermarket nozzles extensively in conjunction with the following buckings and can confirm they all work well:

• OEM KWA bucking (makes a great R-Hop base)
• Prometheus purple
• Prometheus blue flat hop
• G&G green
• Madbull blue
• Guarder 50* clear
• Modify Baton Ryusoku flat hop
• Maple Leaf AST Macaron (minor sanding of the lips may be required due to their length)
• Krytac orange