CMMG ENDEAVOR Mk4 — 22 ARC, 20" Barrel, 10-Round, Midnight Bronze
Brand: CMMG • Series: ENDEAVOR Mk4 (AR-15 platform) • Caliber: 22 ARC (Advanced Rifle Cartridge) • Barrel: 20 inches, threaded • Capacity: 10+1 • Finish/Color: Midnight Bronze • Model/SKU: 28A7F0C-MB / 28A7F0CMB • UPC: 810148627140
Put long-range performance into a light, familiar AR package. The CMMG ENDEAVOR Mk4 in 22 ARC with a 20" barrel is engineered to maximize the 22 ARC’s high-BC .224 projectiles for flatter trajectories, reduced wind drift, and soft recoil. A free-float M-LOK® handguard, optics-ready upper, and handsome Midnight Bronze finish round out this precision-focused, field-ready rifle. From coyotes and prairie dogs to practical precision training and steel out past 600+ yards (shooter and conditions dependent), the ENDEAVOR Mk4 delivers accuracy, consistency, and confidence.
Why 22 ARC + ENDEAVOR Mk4 is a Smart Choice
High-BC, low-recoil ballistics: The 22 ARC is purpose-built around heavy 75–88+ grain .224 bullets, giving you superior downrange efficiency with easier spotting of impacts.
AR-15 handling, big results: Standard controls and parts support mean less weight and more compatibility—without sacrificing reach.
20" velocity sweet spot: Extracts speed and consistency to tighten vertical at distance while staying lively in the hands.
Free-floated precision: A rigid M-LOK handguard keeps support pressure off the barrel for repeatable point of impact from bags, bipods, and barricades.
State-friendly capacity: 10-round magazine included for jurisdictions with capacity limits (always verify local laws).
Key Features
Caliber: 22 ARC (.224 bore, optimized for long, heavy bullets)
Barrel: 20" precision barrel, threaded for brakes, comps, or .22-cal suppressor mounts*
Gas System: AR-15 DI-style operation for smooth cycling and easy maintenance
Handguard: Free-float M-LOK® rail with ample slots for bipods, QD sling cups, ARCA adapters, and night gear
Receivers: AR-15 pattern, optics-ready with continuous Picatinny top rail
Furniture: Adjustable stock and ergonomic grip (configuration may vary by shipment)
Finish: Durable Midnight Bronze for low-glare field use and standout style
Capacity: 10-round detachable magazine included
Model/SKU: 28A7F0C-MB / 28A7F0CMB • UPC: 810148627140
*Confirm thread pitch and device/suppressor ratings before installation.
Performance Advantages You’ll Notice
Flatter holds, fewer corrections: High-BC bullets carry velocity and fight wind, simplifying dope beyond 300 yards.
Stay on target: Mild recoil lets you spot hits through the scope and run faster follow-ups—key for varmints and PRS-style training.
Tripod & barricade ready: Long, stiff handguard and generous M-LOK real estate make stable support easy in any position.
Suppressor friendly: Threaded muzzle supports modern .22-cal cans for reduced blast and better shot calling (where legal).
Ideal Use Cases
Predator & Varmint: Coyotes, foxes, and prairie dogs at distance with minimal recoil fatigue.
Practical Precision Training: Work wind calls and positional mechanics on a gas gun that mirrors your match workflow.
Ranch/Property: Accurate, lightweight field rifle with a durable Midnight Bronze finish that shrugs off weather.
Crossover Long-Range: Stretch your AR-15 platform without going to a heavier big-frame rifle.
Setup Tips for Best Results
Magazines: The 22 ARC typically feeds best from 6.5 Grendel-pattern AR-15 magazines due to case geometry and long COAL bullets.
Optics: Pair with a 3–15x or 4–16x FFP scope with reliable tracking and a wind/holdover reticle.
Support Gear: Add a cant-adjustable bipod and a small rear bag; consider an ARCA plate for tripod stages.
Ammo Selection: Test several 75–88+ grain factory loads; log muzzle velocity (MV) and SDs to build trustworthy dope.
Gas/Buffer Tuning: If running a suppressor or different muzzle device, fine-tune gas and buffer for smooth ejection and minimal dot movement.
Specifications (At a Glance)
Platform: AR-15 / ENDEAVOR Mk4
Caliber: 22 ARC
Barrel Length: 20", threaded
Handguard: Free-float M-LOK
Capacity: 10+1
Finish/Color: Midnight Bronze
Model/SKU: 28A7F0C-MB / 28A7F0CMB
UPC: 810148627140
Note: Exact twist rate, thread pitch, furniture, and included accessories may vary by production. Check your rifle’s package contents for specifics.
Care & Maintenance
Break-in & Clean: Follow CMMG’s guidance; keep the chamber, gas system, and crown clean for best precision.
Torque Matters: Mount optics and M-LOK accessories to spec; use blue threadlocker where appropriate.
Data Discipline: Record MV, density altitude, and wind; the 22 ARC rewards clean data with repeatable hits.
SEO Highlights (Copy & Paste)
CMMG ENDEAVOR Mk4 22 ARC 20" Midnight Bronze
10-round AR-15 precision rifle with free-float M-LOK handguard
Threaded barrel; optimized for heavy .224 bullets and low recoil
Ideal for predator hunting, varmint, and long-range training
Model 28A7F0C-MB / 28A7F0CMB • UPC 810148627140
Frequently Asked Questions
Q: What magazines should I run?
A: 6.5 Grendel-pattern AR-15 magazines typically provide the most reliable feeding with 22 ARC’s case shape and long projectiles.
Q: Is the 20" barrel long enough for distance?
A: Yes—20 inches balances velocity and handling, giving excellent practical long-range performance.
Q: Can I suppress it?
A: The barrel is threaded. Confirm thread pitch and make sure your suppressor is rated for high-velocity .224 centerfire cartridges.
Q: Ideal bullet weights for accuracy?
A: The 22 ARC shines with 75–88+ grain bullets for superior BC and wind resistance.
Q: Are parts AR-15 compatible?
A: Controls and furniture follow AR-15 standards. The 22 ARC uses a Grendel/ARC-style bolt face and generally prefers Grendel-pattern mags.
Precision Without the Punishment
From open country to steel ranges, the CMMG ENDEAVOR Mk4 22 ARC 20" in Midnight Bronze (28A7F0C-MB / 28A7F0CMB, UPC 810148627140) blends long-range capability, soft recoil, and AR-15 familiarity in a rugged, stylish package. Mount quality glass, feed it high-BC ammo, and watch your hit percentage climb.
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