Impact M4: FX Airgun Testing and Overview

Today marks the beginning of a new venture for Ultimate Reloader—airgunning! PCP airguns have advanced far beyond the BB gun stereotype. There are entire competitions devoted to precision airguns as well as a number of devoted airgun hunters. With some support from Utah Airguns, I’m starting this process with an FX Impact M4 topped with a Element Optics Helix 6-24x Gen 2.

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About the FX Airguns Impact M4

The FX Airguns Impact M4 is a top-of-the-line PCP with great modularity.

It is available in four different calibers and three different barrel lengths.

We topped a .22 caliber 600mm rifle with the new Helix Gen 2 6-24×50 FFP scope we recently tested on our .22 ARC build.

Just like tricking out an AR, there are a number of available accessories to customize your airgun. Our standard Impact M4 arrived with an AirMarksman Backbone Rail and Loki Rail installed by Utah Airguns.

The Backbone Rail has 30 MOA of inclination built in for greater elevation while the Loki Rail maximizes ARCA accessory capability.

We also added a IA-1350 moderator from Impulse Air. A moderator is essentially a suppressor, but for AIRGUN USE ONLY.

From Utah Airguns:

The Impact M4 Standard comes in either black or copper and is available in .177, .22, .25, and .30 calibers. It has a barrel length of 600mm and an overall length of 860mm (or 34″). The high-capacity magazines on the FX Impact M4 have been redesigned and are now made from a stronger material with a new internal mechanism, ensuring that the inner drum rotates smoothly even when fully loaded with some of the heaviest slugs on the market.

The single regulator design is standard on the M4 and features FX’s new brass piston regulator. It is stronger, has faster refresh rates, is more consistent, and can easily handle higher bottle pressures with a max working pressure of 170bar.

When it comes to design, the Impact M4 has been given a new design without straying too far from the original iconic look. This has been accomplished through several small, yet important improvements throughout the entire platform: subtle new lines, cutouts for easy access to certain parts, and angles to tie it all together and make the M4 both more practical and pleasing to the eye.

To further enhance both performance and the shooting experience of the FX Impact M4, you can expect improvement on the overall rigidity thanks to the design of a new top plate. It is significantly thicker and stronger, bringing more rigidity throughout the entire platform. The M4’s redesigned picatinny optics rail mounts to an 11mm dovetail rail machined into the factory backbone. This eliminates alignment issues when removing and reinstalling the optics rail. The Picatinny optics rail can also be loosened so it can slide along the 11mm dovetail rail and be re-clamped closer to the shooter, allowing the shooter to fine-tune eye relief for their chosen optic.

The new quick set trigger system was one of the first major upgrades added to the M4. At the foundation of each great shot taken is the trigger. The quick set trigger on the M4 allows for extensive adjustability based on the shooting scenario: adjust from just the right amount of pull for a hunting application to a match grade trigger that is light, clean, and crisp!

With the new quick set trigger unit and top rail added, FX also improved the overall feel and comfort of shooting the Impact with the new FX grip. The design of the new grip is more defined and comfortable to grip onto, with just the right amount of palm swell and beaver tail to enhance comfort while shooting and giving you a firm hold on your Impact M4.

The FX Impact M4 is available in a variety of calibers, sizes, and colors:

COLORS:

- Black
- Copper

CALIBERS / MAGAZINE CAPACITY:

- .177 / 34 shots
- .22 / 28 shots
- .25 / 25 shots
- .30 / 23 shots

OTHER LENGTHS AVAILABLE:

- Barrel Length / Overall Length
- Compact: 500mm / 640 (Black or Copper)
- Sniper: 700mm / 1000mm (Black or Copper)
- Extended: 800mm / 1120mm (Black or Copper)

Filling the Gun

Airguns require some different equipment than firearms do. While more cost effective to shoot, you have to have a way to fill the gun. I utilized an Air Venturi ROV Air compressor to fill my AirMarksman carbon fiber tank.

This tank is what I will take to the range. I plugged in the compressor, then connected the hose and shut the release valve.

At this point, I opened and closed the bleeder valve to ensure there was no pressure, connected the hose, opened the tank, and turned the compressor on.

The compressor automatically shut itself off when the tank was full. To disconnect it, I shut the main valve, bled off the air in the line, and removed the hose.

To fill the gun, I used a quick disconnect fitting on a longer hose and slowly opened the tank, keeping an eye on the pressure gauge on the M4.

Maximum pressure is 250 bar. Compressed air can be dangerous – remember to keep your head away from any lines and fittings that may come off if not fully secured.

Also remember to always bleed off extra air before disconnecting a line. For more details on filling an Impact, be sure to check out Utah Airguns’ YouTube channel.

First Shots

The .22 caliber impact has a 28-shot rotary magazine. Take the spring-loaded turret and spin it until full tension. Gently place a slug in the first hole to hold the spring tension and fill the magazine from there.

The slugs should go nose down. I replaced the clear plastic cover and loaded the gun. I could not boresight this rifle, so I started 30 feet from the target and made some preliminary adjustments before fully zeroing at 50 yards.

At this point, zeroing the air rifle is the same as zeroing for any other gun. Just be sure to keep an eye on the pressure gauge to ensure you have enough air to send consistent shots downrange.

Our best three-shot 50 yard group measured 0.256” with .22 caliber 30 Grain Javelin Gen 2 slugs.

This gun was incredibly fun to shoot with a crisp trigger and ZERO recoil. I shot it both with the included moderator and the modular .30 caliber moderator from Impulse Air.

Impulse Air IA-1350 on the FX Airgun Impact M4

Varmint Hunting and Steel Targets

My main goal with this rifle was to continue to control our rock chuck population. It performed well and was incredibly quiet, providing even more shot opportunities.

After some pest control, I engaged some rimfire steel from D-M Targets out to 100 yards.

Anatomy of the Impact M4

Moving forward, I look forward to learning how to tune the Impact and perform caliber changeovers, but I wanted to start with an anatomy overview.

Under the buttstock is a regulator pressure gauge. This displays the output and pressure per shot.

In front of this gauge is the Power Plenum 750, which provides constant pressure during the firing cycle.

The gun is filled by connecting to the male quick connector ahead of the trigger.

This is very similar to working with pneumatic tools.

Behind the air tank sits the valve adjuster for primary pressure regulation.

This can be fine tuned using the micro power adjuster (fine tune barrel roller) above the grip and the rear macro power adjuster (hammer power wheel).

The main regulator is inside the rifle.

Conclusion

Shooting the Impact M4 with slugs felt a lot like shooting rimfire. While I’ve had experience with BB guns and air pistols, this was on an entirely different level and I have a lot to learn.

Everything is different from centerfire, from filling the tank to loading the magazine, but don’t let it intimidate you.

I’m fortunate to have a number of friends with air rifle experience to ask for advice and look forward to diving more into the minutia of precision airgunning. If you have specific questions, please drop us a note!