Field Report · Collared Doves
FX Impact M4 vs Texan .257: accuracy beat power
By James · Updated September 24, 2026 · Editorial policy
Field protocol: every load gets a 10-shot chronograph string (average velocity, extreme spread, energy) before it's trusted on game. Holdovers are confirmed at real distances, then re-confirmed in field conditions. Shots are recorded through the scope cam, and claims on this page link to footage where it exists. Full methodology & editorial policy →
The full hunt: the plan, the Texan's valve problem, and the Impact finishing the day.
The plan: scalpel vs sledgehammer
The idea was simple. Put a precise .22 against a big-bore .257 on the same birds, same day, same hands, and see whether the heavier slug made anything easier. Here's what went out:
| FX Impact M4 | AirForce Texan .257 | |
|---|---|---|
| Caliber / projectile | .22, 40.1gr ACE FRAG slug | .257, 60-grain-class slug |
| Optic | DNT Zulus 4K scope cam | Arken EP4 6-24x |
| Action | Regulated, magazine-fed repeater | Single-shot big-bore |
| Max fill pressure | 250 bar (3,625 psi) | 3,000 psi (AirForce listing for the Texan SS .257) |
| Muzzle energy | ~80 FPE (40.1gr at ~950 fps as tuned) | Much higher; big-bore class |
| What it's built for | Precision on small game at range | Energy for larger animals |
What actually happened
When I filled the Texan, it developed a valve problem. The cause turned out to be a cracked valve O-ring, and that took it out of the hunt. So the comparison became something more useful: one rifle, no backup.
The Impact carried the day. I took 15 shots at birds from about 30 to 130 yards and recovered 5. The misses clustered at the long end. Inside about 100 yards, the Impact is in its sweet zone. Past that, range and wind errors show up fast, and I own every one of those misses.
Why a bad valve ruins long shots
A PCP's valve and regulator decide how fast each shot leaves the barrel. When a seal fails or the valve behaves inconsistently, velocity starts swinging from shot to shot. At 20 yards you barely notice. At 100+ yards, speed differences become inches, because slower shots are in the air longer and drop more.
| Distance | Drop at 950 fps | Drop at 910 fps | Vertical shift from a 40 fps spread |
|---|---|---|---|
| 50 yd | 4.8 in | 5.2 in | 0.4 in |
| 80 yd | 12.3 in | 13.4 in | 1.1 in |
| 100 yd | 19.3 in | 21.0 in | 1.7 in |
| 120 yd | 27.7 in | 30.2 in | 2.5 in |
| 150 yd | 43.3 in | 47.2 in | 3.9 in |
Computed as gravity drop with no air drag (a best case). Real drag adds time of flight, so the true shift is larger. A collared dove's vital zone is only a couple of inches tall.
A valve problem doesn't just cost you shots. It makes your holds meaningless. If you ever see the same hold printing in different places, stop and check the rifle before you blame yourself. How to diagnose an inconsistent PCP →
The verdict
For small game, the Impact M4 wins, and it isn't close
The Texan is a big-bore platform. Its power is for animals much bigger than a dove, and a small-game hunt never uses it. For collared doves, rabbits, and squirrels, the things that matter are accuracy, a consistent shot string, fast follow-ups, and a rifle that works every time you fill it. The .22 gave me all four. As I put it in the video: the animal doesn't score your equipment, it scores your shot.
That's not a verdict on the Texan's reliability. One O-ring failure on one day is one data point, and a fair test of the Texan would be on animals that actually need big-bore energy.
What I'd take from this
- Pick the rifle for the quarry, not the spec sheet. Small game needs about 12 FPE at the animal (chart). My M4 makes about 80.
- Bring a backup plan. Spare O-rings, a fill probe that fits, and a second rifle if the trip matters.
- Fill carefully. Fill slowly, watch the gauge, and don't exceed the rifle's rated pressure.
- Accept your range. My misses at 110–130 yards are why the long-range guide is as cautious as it is.
More on the rifle that did the work: FX Impact M4 review and my exact slug setup.
FAQ
FX Impact M4 or AirForce Texan .257: which is better for small game?
For doves, rabbits, and squirrels, the FX Impact M4 in .22. It's accurate, repeating, regulated, and carries more than enough energy for small game. The Texan .257 is a big-bore platform with far more power than small game needs; its advantage is energy on larger animals, not accuracy on small targets.
What happened to the Texan .257 on the hunt?
It developed a valve problem when I filled it (a cracked valve O-ring), which took it out of the hunt. The Impact M4 carried the whole day.
Does more power make an air rifle better for hunting?
Not past the energy your quarry needs. A .22 slug in the right spot kills a collared dove as dead as a .257 slug. What decides the hunt is accuracy and a rifle that works every time.
How much does velocity spread affect accuracy at long range?
More than people expect. Ignoring air drag, a 40 fps difference on a 950 fps slug moves the impact about 1.7 inches vertically at 100 yards and about 2.5 inches at 120 yards. Drag makes the real number bigger. That's why a leaking or failing valve ruins long shots.
Sources
- Airgun Depot — FX Impact M4 specifications
- AirForce Airguns — Texan SS .257 specifications
- Airgun Depot — AirForce Texan guide
- Pyramyd AIR blog — Common PCP leaks and some common fixes (Tom Gaylord)
Keep reading
Is the FX Impact M4 Worth It for Hunting?
Months of hunts, independent accuracy data, the full system cost, and who shouldn't buy one.
Read the review →Why Is My PCP Shooting Inconsistent?
Leaks, regulator creep, fill pressure, and the valve failure that took my Texan out of a hunt.
Diagnose it →Eurasian Collared Dove Hunting With an Air Rifle
ID, legality, energy, shot placement, where to find them, and how I hunt them with slugs.
Read the guide →