CMMG Endeavor 100 Mk4 350 Legend 16″ Rifle

Description

Picture this: you’re on a Missouri deer stand at last light, and a legal-opportunity buck steps into a clearing at 150 yards. You need a cartridge that hits with authority, a platform you can trust in the cold, and a rifle that won’t let you down when it counts. That’s the exact scenario the CMMG Endeavor 100 Mk4 350 Legend, 16″ Barrel, Black was built for. It bridges the gap between the AR-15’s modularity and the hard-hitting performance required for medium game, all in a straight-wall cartridge legal for deer hunting in numerous states, including Missouri.

The CMMG Endeavor 100 Mk4 350 Legend, 16″ Barrel, Black is a purpose-built, modern sporting rifle chambered in the potent 350 Legend cartridge. It features a 16-inch barrel for a balanced, maneuverable profile, a mil-spec compatible AR-15 platform for customization, and is designed for reliable performance in hunting and defensive scenarios where more power is required. This isn’t a plinker; it’s a tool for a specific job. The 350 Legend cartridge delivers significantly more energy downrange than 5.56 NATO, with manageable recoil and excellent terminal performance on game up to deer-sized animals. At $986.90, it represents a serious investment in a dedicated hunting or ranch rifle that leverages the familiar AR-15 manual of arms.

Let’s break down what makes this rifle stand out. The heart is that 16-inch barrel, cold hammer-forged for durability and accuracy. It’s the sweet spot for the 350 Legend—long enough to let the cartridge develop its full ballistic potential without becoming unwieldy in a blind or thick brush. The rifle uses a direct impingement gas system, tuned for reliability with a wide range of 350 Legend ammunition, from supersonic hunting loads to subsonic options. The upper and lower receivers are machined from 7075-T6 aluminum, providing a rigid foundation. One of the biggest practical advantages? It’s drop-in ready for anyone familiar with the AR platform. The rifle ships with a 10-round magazine, a sensible choice for hunting regulations, and the lower receiver is compatible with many aftermarket AR-15 triggers and grips, allowing for fine-tuning to your preference.

Here are the key specifications laid out clearly:

Caliber	350 Legend
Barrel Length	16 inches
Overall Length	34.5 inches (stock collapsed)
Weight	6.5 lbs (unloaded)
Magazine Capacity	10 Rounds (included)
Action	Direct Impingement Semi-Auto

So, what’s the real-world take? The pros are clear: you get a hard-hitting, straight-wall cartridge in a lightweight, customizable platform you already know how to run. Recoil is mild—sharper than a 5.56 but far gentler than a .308—making follow-up shots fast. The cons? Ammunition cost is higher than .223/5.56, and while availability is good, it’s not as ubiquitous as other calibers. Also, the 350 Legend’s performance shines within 250 yards; it’s not a long-range precision cartridge. That said, for its intended roles, those are acceptable trade-offs.

Who is this rifle for? Primarily, it’s for the Missouri hunter who wants a modern, semi-automatic option for deer season in a legal cartridge. It’s also for the rural landowner who needs a capable rifle for property defense where penetration through barriers is a concern, or for dispatching predators. If you’re looking for a versatile, powerful upper to pair with a standard AR-15 lower you already own, the Endeavor 100 Mk4 makes a compelling case as a dedicated upper receiver group.

Frequently Asked Questions

Q: Is the 350 Legend a good deer cartridge for Missouri?

A: Absolutely. The 350 Legend meets Missouri’s straight-wall cartridge requirements for deer hunting in specific zones and seasons. It delivers ample energy for ethical takedowns of whitetail deer within typical hunting ranges, often with less recoil than traditional hunting rifles.

Q: Will this rifle work with my existing AR-15 magazines and lower?

A: The lower receiver is a standard mil-spec AR-15 pattern and will accept many aftermarket triggers and grips. However, the 350 Legend requires specific magazines due to its larger case diameter. The rifle includes a dedicated 10-round mag, and it is compatible with CMMG’s 350 Legend magazines and certain other branded variants designed for the caliber.

Q: What optics or accessories are recommended?

A: A low-power variable optic (LPVO) in the 1-6x or 1-8x range is an excellent match for this rifle’s capabilities, perfect for quick shots in brush or more precise aim at distance. A sturdy two-point sling and a weapon light round out a highly effective setup for both hunting and home defense roles. This rifle is available at firearms-missouri.com for Missouri residents and nationwide, and an FFL transfer is required for firearm purchases.

If the idea of a capable, modern rifle built for a specific purpose aligns with your needs, the CMMG Endeavor 100 Mk4 in 350 Legend deserves a close look.