CMMG Endeavor MK4 .22 ARC

The CMMG Endeavor MK4 sits at the top of CMMG’s semi-auto lineup for hunters who want to push 22 ARC as far as a gas gun will allow. The 20-inch medium-heavy barrel is the defining feature here – it adds roughly 250 fps over the 16.1-inch Resolute and closes the gap with bolt guns enough to matter at 500-plus yards. At $1,300–$1,400 street, this is a purpose-built varmint AR for prairie dog and coyote hunters who need semi-auto follow-up speed without sacrificing meaningful range.

Quick Verdict: CMMG Endeavor MK4 .22 ARC

✓ Best for: Prairie dog and coyote hunters wanting maximum semi-auto 22 ARC velocity
✓ Price: $1,300–$1,400 street
✓ Key strength: 20" barrel adds ~250 fps over 16.1" alternatives – meaningful at 500+ yards
✗ Not ideal for: Budget buyers or shooters who want maximum precision without a trigger upgrade

Real-World Performance at 500+ Yards

The CMMG Endeavor MK4 22 ARC delivers genuine performance gains over shorter-barreled 22 ARC semi-autos. Running Hornady 88gr ELD-M, expect approximately 2,950 fps from the 20-inch barrel – that’s around 250 fps more than the 16.1-inch Resolute produces with the same load, and it translates to noticeably flatter trajectories and better retained energy past 400 yards. The 75gr ELD-M pushes to roughly 3,150 fps, and the 62gr ELD-VT hits around 3,300 fps for flat-shooting varmint work. Factory accuracy with the 6-lb RDB trigger runs 1.0–1.5 MOA at 100 yards – serviceable but not impressive. Swap in a Geissele SSA-E and that tightens to 0.5–0.8 MOA, which is approaching bolt-gun territory and sufficient for consistent hits on prairie dogs at 500 yards. The medium-heavy contour manages heat well across extended strings, which matters during a full day of prairie dog shooting where a light-contour barrel would walk shots after 20 rounds.

Applications & Use Cases for Varmint Hunters

Prairie dog shooting is where the CMMG Endeavor MK4 22 ARC earns its keep. The 20-inch barrel gives you enough velocity to stretch 88gr ELD-M to 500–600 yards with confidence, and semi-auto follow-up lets you work a dog town efficiently – hitting and following up within two seconds versus five-plus on a bolt gun. The medium-heavy barrel handles the heat of extended strings better than lighter contours at this price point, which is a real consideration when you’re burning through 200 rounds in an afternoon. For coyote calling, the semi-auto capability shines when multiple animals respond – you get a fast second shot that a bolt gun simply can’t match, and the 20-inch barrel gives you enough range to reach coyotes that hang up at distance. Suppressed varmint work is straightforward with the 5/8×24 threaded muzzle – the platform runs reliably suppressed, and the semi-auto action cycles smoothly with a can attached. Where the Endeavor falls short is as a dedicated long-range precision tool past 600 yards; at that distance, a quality bolt gun with a match trigger still outperforms this platform even after a trigger upgrade, and the 7.5-lb weight becomes a liability on long carries.

Ergonomics & Handling in the Field

The CMMG Endeavor MK4 22 ARC handles like a well-built AR-15, which is exactly what it is. The MFT Minimalist collapsible stock adjusts for different shooters and body armor setups, and the M-LOK handguard gives you a clean, full-length grip surface for prone work with a bipod. At 7.5 lbs unloaded, it’s heavier than bolt-gun alternatives in the same caliber – add a scope, bipod, and loaded magazine and you’re looking at 10-plus lbs in the field. That weight is manageable for truck-based prairie dog hunting where you’re not hiking miles, but it’s noticeable on a long coyote stalk. The 40.5-inch overall length with stock extended is the trade-off for the 20-inch barrel’s velocity gains – if compactness matters more than range, the Resolute’s 16.1-inch barrel is the better choice.

Aftermarket & Upgrade Path for Precision Gains

The CMMG Endeavor MK4 22 ARC runs on the standard AR-15 platform, which means the aftermarket is essentially unlimited. The first and most important upgrade is the trigger – the factory 6-lb RDB single-stage needs to go before you can use this rifle’s full accuracy potential. A Geissele SSA-E at $240 or a TriggerTech AR at $200 transforms the shooting experience and drops groups from 1.0–1.5 MOA to 0.5–0.8 MOA. Budget that upgrade alongside the rifle purchase – realistically, plan $1,500–$1,650 all-in for a complete precision semi-auto 22 ARC setup. Beyond the trigger, a quality optic like the Vortex Viper PST Gen II 5–25×50 lets you use the 20-inch barrel’s full range capability, an Atlas BT10 bipod handles prone varmint work, and the 5/8×24 threaded muzzle is suppressor-ready for a SilencerCo Omega 300 or similar. Standard AR-15 PMAG compatibility keeps magazine costs low.

Pros & Cons – Is the 20" Worth It?

Strengths:
✓ 20-inch barrel produces ~2,950 fps with 88gr ELD-M – ~250 fps more than 16.1-inch alternatives
✓ Medium-heavy contour manages heat across extended varmint strings better than light profiles
✓ Standard AR-15 platform – unlimited aftermarket, familiar controls, PMAG compatibility
✓ 5/8×24 threaded muzzle – suppressor-ready out of the box
✓ M-LOK handguard – full accessory compatibility for bipods, lights, and foregrips
✓ Collapsible MFT stock – adjustable for varied shooters
✓ Multiple Cerakote color options – practical for field use and weather resistance
✓ 0.5–0.8 MOA achievable after trigger upgrade – competitive with mid-tier bolt guns

Limitations:
✗ Factory 6-lb trigger – requires $200–$240 upgrade before the rifle reaches its accuracy potential
✗ 7.5 lbs unloaded – heavier than bolt-gun alternatives with similar effective range
✗ $1,300–$1,400 street – $700 more than budget 22 ARC ARs like BCA for similar basic function
✗ 40.5-inch OAL – less compact than 16-inch alternatives; not ideal for tight blinds or vehicle use
✗ Semi-auto ammo consumption – practice costs add up faster than bolt-gun equivalent
✗ Bolt guns still outperform at 600+ yards even after trigger upgrade

Competitors & Alternatives Worth Considering

*After trigger upgrade

The CMMG Resolute MK4 22 ARC is the most direct comparison – same rifle, 4 inches shorter, similar price, and the right choice if compactness matters more than velocity. The Rise Armament Watchman XR 22 ARC costs $100–$200 more but includes a billet receiver and better factory trigger, making it the smarter buy if you want to avoid the trigger upgrade cost. The Faxon Firearms 22 ARC undercuts the Endeavor on price with a match-grade barrel and is worth a hard look if budget is the primary concern – the Faxon match barrel is genuinely competitive with the CMMG’s medium-heavy profile at distance.

Who Should Buy This Rifle?

The CMMG Endeavor MK4 22 ARC is the right call for varmint hunters who want the most velocity available from a semi-auto 22 ARC and do most of their shooting from a truck or fixed position where the 7.5-lb weight isn’t a penalty. If you’re burning through prairie dogs at 400–600 yards and need fast follow-up shots, this platform delivers in a way no bolt gun can match. Look elsewhere if you’re on a tight budget – the BCA 22 ARC saves $700 for similar basic function – or if you want maximum precision past 600 yards, where a quality bolt gun like the Ruger American Gen II Predator 22 ARC outperforms at $700 less.

Frequently Asked Questions

Q: Does the 20-inch barrel make a meaningful difference over 16-inch options?
A: Yes – roughly 250 fps with 88gr ELD-M, which matters at 500–600 yards for trajectory and energy retention.

Q: Is the factory trigger acceptable for varmint hunting?
A: At 6 lbs, it’s functional but limits accuracy to 1.0–1.5 MOA. Budget $200–$240 for a Geissele SSA-E or TriggerTech AR upgrade.

Q: Will standard AR-15 magazines work?
A: Yes – standard AR-15 PMAGs are compatible. The rifle ships with a 10-round PMAG.

Q: Is the Endeavor suppressor-ready?
A: Yes – the 5/8×24 threaded muzzle accepts most suppressors including the SilencerCo Omega 300.

Q: How does it compare to a bolt gun for precision at distance?
A: After a trigger upgrade, it reaches 0.5–0.8 MOA – competitive to 500 yards, but bolt guns still have the edge past 600.

Q: What optic pairs best with the 20-inch barrel’s range capability?
A: A Vortex Viper PST Gen II 5–25×50 or similar high-magnification optic lets you use the full 500–600 yard effective range.

Final Verdict – CMMG Endeavor MK4 .22 ARC

The CMMG Endeavor MK4 22 ARC is the best semi-auto 22 ARC option for hunters who prioritize velocity and follow-up speed over compactness and weight. Budget $200–$240 for a trigger upgrade alongside the purchase – without it, you’re leaving accuracy on the table. At $1,500–$1,650 all-in with a quality trigger, it’s a capable 500-yard varmint platform that no bolt gun can match for fast follow-up shots.

The CMMG Endeavor MK4 22 ARC fills a specific niche well – it’s the semi-auto 22 ARC to buy when you need the velocity of a 20-inch barrel and the speed of a gas gun in the same package. It’s not a budget rifle, and it’s not a substitute for a precision bolt gun at extreme range. But for prairie dog hunters who want to reach past 500 yards and still run fast strings, it’s the most practical tool in the 22 ARC semi-auto market at this price point.