Short answer: choose the FX Impact M4 if you want a modular, highly tunable bullpup with four barrel lengths and swappable calibers, and choose the Karma EQ if you want a high-power bullpup with a 500cc air supply and a published power ceiling of up to 100 FPE in .30 caliber. Both are regulated, magazine-fed PCP bullpups, so the decision comes down to fill pressure, adjustability and how you shoot.
The Karma EQ is the closest Karma competitor to the Impact M4 in our catalog because both are compact bullpups aimed at hunters and precision shooters. Karma's Red Panda is a dedicated benchrest rifle, and the SLS is a side-lever semi-auto, so neither is a like-for-like match.
FX Impact M4 vs Karma EQ: Spec Comparison
| Spec | FX Impact M4 (Standard) | Karma EQ |
|---|---|---|
| Form factor | Bullpup | Bullpup |
| Calibers | .177, .22, .25, .30 (.35 sold as a separate model) | .22, .25, .30 |
| Barrel length | 600mm (Compact 500mm, Sniper 700mm, Extended 800mm) | 609mm / 24 in |
| Overall length | 860mm / 34 in | 850mm |
| Magazine capacity | .177: 34, .22: 28, .25: 25, .30: 23 | .22: 28, .25: 26, .30: 22 |
| Max fill pressure | 250 bar with the single-regulator setup (FX owner's manual) | 310 bar |
| Air capacity | 480cc (Standard) | 500cc |
| Regulator | AMP brass piston regulator, 170 bar max working pressure | External adjustable regulator, 70cc plenum |
| Optics rail | Picatinny rail that slides on an 11mm dovetail backbone | 20 MOA Picatinny |
| Published energy | Not listed on our product page | Up to 65 FPE (.22), 80 FPE (.25), 100 FPE (.30) |
| Published shot count | Not listed on our product page | Up to 160 (.22), 110 (.25), 50 (.30) |
Sources: our product pages for each rifle and the FX Impact M4 owner's manual. The 480cc figure is from the fill-time chart on our Air Venturi Nomad Nano listing.
Where the FX Impact M4 Wins
Length options in one platform
The Impact M4 comes in Compact (500mm barrel, 640mm overall), Standard (600mm, 860mm), Sniper (700mm, 1000mm) and Extended (800mm, 1120mm). There is also a .35 caliber Impact M4. That range lets you match the rifle to a truck, a blind or a bench.
Fine-grained tuning
FX describes the M4's brass piston AMP regulator as stronger, faster-refreshing and more consistent than before. The quick set trigger adjusts from a hunting pull to a light match-style break, and the redesigned top plate adds rigidity. If you like to tune for a specific pellet or slug, the M4 gives you a lot of control.
Accessory ecosystem
Saber Tactical makes M4-specific parts we stock, including the M4 cheek riser, ambidextrous cheek rest and TRS rail.
Where the Karma EQ Wins
More air at a higher fill pressure
The EQ fills to 310 bar and holds 500cc. The Impact M4's single-regulator setup is limited to 250 bar overall. More stored air generally means more shots per fill at a given power level, and Karma publishes shot counts of up to 160 in .22.
Published power for heavy slugs
Karma built the EQ around a 70cc plenum and adjustable valve to push heavy-for-caliber slugs, with published energy of up to 100 FPE in .30. If you mainly hunt with slugs, that headroom is the EQ's main selling point.
Simple, robust layout
The EQ has a 2-stage adjustable trigger, a push-button safety, a 20 MOA Picatinny rail and a 1/2x20 UNF threaded shroud for airgun moderators. Spare EQ magazines are in stock.
Which One Should You Buy?
- Mostly pellets, precision and tinkering: FX Impact M4.
- Heavy slugs and hunting power: Karma EQ in .25 or .30.
- Want .177: only the Impact M4 is offered in .177.
- Need the shortest package: Impact M4 Compact at 640mm overall.
- Fill source tops out at 250 bar: either works. Just fill the EQ to the pressure your source supports.
Frequently Asked Questions
Is the FX Impact M4 better than the Karma EQ?
Neither is better overall. The Impact M4 offers more length and caliber options and deeper tuning. The Karma EQ offers higher fill pressure, more air and published power figures aimed at heavy slugs.
What is the fill pressure of the FX Impact M4?
FX's owner's manual lists a 250 bar maximum system pressure for the single-regulator setup and 300 bar for a dual-regulator setup. The regulator itself has a 170 bar maximum working pressure.
What is the fill pressure of the Karma EQ?
Our product page lists 310 bar for the EQ's 500cc aluminum air cylinder.
Can both rifles shoot slugs?
Yes. FX says the M4's redesigned magazines handle some of the heaviest slugs on the market, and Karma designed the EQ to drive heavy-for-caliber slugs and pellets.
Can I put a moderator on either rifle?
The Karma EQ shroud is threaded 1/2x20 UNF. For the Impact M4, check the current product page or ask us which adapter fits. Always follow local laws.
Always follow the manufacturer manual, wear eye protection, and know your local laws before buying, carrying or shooting an airgun.
Talk to The Pellet Shop
Have a question about a specific rifle, caliber or setup? Visit our showroom in Westbury, NY, call or text (718) 450-4146, or email info@ThePelletShop.com. You can also browse every airgun we carry online. Specs in this article come from our product pages and manufacturer documentation and can change, so check the current product page before you buy.