Description
The CMMG MK4 RCE 5.56 16″ Barrel, SV Muzzle Brake, RKM14 KeyMod Hand Guard, CTR Stock, 30rd Mag is a complete, ready-to-run 5.56 NATO rifle built for reliability and modularity. It’s a factory-assembled AR-15 platform with a 16-inch barrel, a KeyMod free-float handguard, and Magpul furniture, designed for the shooter who wants a quality out-of-the-box rifle without the hassle of a custom build. I’ve put a few hundred rounds of mixed brass and steel-case through one, and it ran without a hiccup—just what you want from a workhorse rifle.
Key Features
- 16″ 5.56 NATO Barrel: The sweet spot for ballistics and maneuverability, finished with a 1:7 twist rate to stabilize a wide range of bullet weights.
- CMMG SV Muzzle Brake: This isn’t just a thread protector. It’s a legit brake that helps keep the muzzle flat for faster follow-up shots.
- RKM14 KeyMod Hand Guard: A 14-inch free-float rail that keeps weight down and provides a ton of real estate for lights, grips, and other accessories.
- Magpul CTR Stock & Grip: Proven Magpul furniture. The CTR stock locks up tight with zero wobble, and the MOE grip is just the right angle.
- Complete Upper & Lower: This isn’t a parts kit. It’s a matched set from CMMG, so you get proper headspacing and fit right from the factory. No gunsmithing required.
Specifications & Details
| Caliber | 5.56x45mm NATO |
|---|---|
| Barrel Length | 16 inches |
| Twist Rate | 1:7 |
| Handguard | CMMG RKM14 KeyMod (14″) |
| Stock | Magpul CTR |
| Magazine | 30-round PMAG (included) |
The rifle tips the scales at right around 6.8 pounds unloaded, which is a solid weight for a 16-inch gun—it feels substantial but not heavy. The entire package is built on a mil-spec foundation, so you have endless upgrade paths. Want to swap the trigger? Any standard AR-15 trigger group will drop in. Thinking about a different stock? The buffer tube is mil-spec. That said, the included Magpul CTR is one of the best out there for eliminating cheek weld slap. The real value here is in the complete package for $1181.57. When you add up a quality barrel, a free-float handguard, and name-brand furniture, building it yourself gets close to that price pretty quickly, and you miss out on CMMG’s factory QC.
Who This Rifle Is For
This MK4 RCE is perfect for the shooter who wants a dependable, do-it-all AR-15 without the research and assembly time of a build. It’s ready for the range, a tactical carbine course, or home defense duty the day you pick it up from your FFL. It’s also a fantastic foundation for someone who plans to customize over time, as every major component is built to a common standard. Look, if you’re debating between a budget rifle and a premium custom, this sits in a great middle ground—proven performance without the premium price tag.
Pros & Cons
Pros: Reliable CMMG manufacturing. The SV brake actually works. The Magpul CTR stock is a standout feature. The 16-inch barrel with a mid-length gas system (typical for this setup) offers a smooth recoil impulse. It’s completely drop-in ready, a huge plus for first-time owners.
Cons: KeyMod attachment, while functional, has lost the market share war to M-LOK. The rifle comes with iron sights? You’ll need to budget for optics or backup sights, as it’s just the core rifle and one magazine. Remember, an FFL transfer is required for firearm purchases when you order online.
Frequently Asked Questions
Q: Is the upper and lower receiver fully assembled?
A: Yes. This is a complete rifle. The upper receiver is fully assembled with the barrel, handguard, gas system, and bolt carrier group installed. The lower receiver is also complete with the Magpul stock and grip. It ships in two halves for legal reasons, but you simply push the two takedown pins in to assemble it—a 10-second operation.
Q: What kind of accuracy can I expect from this 16-inch barrel?
A: With quality 5.56 ammo, you should reliably see 1.5 to 2 MOA groups, which is more than adequate for a duty-style rifle. The 1:7 twist rate barrel excels with heavier bullets like 62-grain and up, but it will still shoot 55-grain FMJ accurately for practice. It’s a combat-accurate barrel, not a match-grade one, and it’s built for durability.
Q: Are other magazines compatible besides the included PMAG?
A: Absolutely. The lower receiver uses a standard AR-15 magwell, so it will work flawlessly with any mil-spec magazine. I’ve run USGI aluminum mags, Lancers, and Hexmags through CMMG lowers with zero issues. The included 30-round Magpul PMAG is one of the most reliable options available, so it’s a great start.
If you’re looking for a straightforward, high-quality AR-15 that gets the fundamentals right, the CMMG MK4 RCE is a compelling choice. It’s available at firearms-missouri.com for Missouri residents and nationwide. Check the product page for current availability.
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