The Swedish manufacturer FX Airguns introduces the fourth generation of one of the most successful PCP air rifles called Impact M4. And it is not just an upgrade – almost all external and internal components have been redesigned. However, it still retains the characteristic style of the Impact series.
The main frame holding everything together has been reinforced for overall increased rigidity of the air rifle and is now equipped with a hidden 11 mm dovetail. Thanks to this, the 22 mm Picatinny mounting rail can be moved forwards and backwards, giving you more freedom when installing a riflescope. The sliding rail is canted 30 MOA, making it easier to zero the riflescope for long‑range shooting.

The entire trigger mechanism has also undergone major changes. Impact M4 features the so‑called “Quick Set Trigger” – a trigger that you can easily adapt to any purpose. So whether you plan to go hunting with a heavier trigger, or to a shooting competition that requires maximum sensitivity, you can adjust the air rifle using a single screw in just a few seconds.
The externally adjustable AMP MkII pressure regulator with a brass piston has likewise been modernised. It is much more durable, more responsive, ensures even more consistent muzzle velocity and can handle a maximum regulated pressure of up to 170 bar.
The high‑capacity magazine has also been redesigned. It is now made of Polyoxymethylene (POM), and its new internal mechanism ensures smooth rotation even when using the heaviest available ammunition. The AR‑15 style grip is more robust and textured in the contact areas for better shooting comfort.

Everything else remains unchanged. The shrouded barrel with externally pressed rifling is as perfectly accurate as ever, the air rifle comes with a sound moderator with 1/2" UNF thread, the carbon bottle can be filled up to 250 bar, the rifle features two WIKA manometers (one for the bottle pressure, the other for the regulator), there are three Picatinny rails on the sides and under the barrel, the hammer spring preload can be adjusted using the micro and macro dials of the Quick Tune System, behind the regulator there is a large 75 cc power plenum, the sidelever can be swapped to the other side by removing just two screws, the safety is located on the right side, the buttpad is height‑adjustable, and the bottle is filled via a standard Foster quick coupling with 1/8" BSP thread.
FX Impact M4 air rifle variants
- Compact – Superior STX 500 mm barrel, 300 cc carbon bottle
- Standard – Superior STX 600 mm barrel, 480 cc carbon bottle
- Sniper – Superior STX 700 mm barrel, 580 cc carbon bottle
- Extended – Superior Heavy STX 800 mm barrel, 580 cc carbon bottle
- Copper – colour variant with copper anodising