Maxim Defense MDX 516 5.56 16″ 30RD ARID FDE

Description

The Maxim Defense MDX 516 5.56 16″ 30RD ARID FDE is a no-nonsense, semi-auto AR-pattern rifle built for folks who need a tool that works day in and day out. Chambered in .223 Rem/5.56 NATO, it comes with a 16-inch barrel, a 30-round magazine, and a Flat Dark Earth finish that shrugs off dirt and scuffs. This is a utility rifle for range work, varmint control, or general-purpose shooting—nothing fancy, just reliable.

Manufacturer	Maxim Defense
Model	MDX 516
Material	7075-T6 aluminum receiver, steel barrel (per manufacturer specs)
Compatibility	Standard AR-15 lower parts, .223 Rem/5.56 NATO ammunition
Finish	Flat Dark Earth (ARID FDE)
Weight	6.8 lbs (unloaded, per manufacturer specs)
Condition	New

Key Features

• 16″ Chrome-Lined Barrel – WHY IT MATTERS: That chrome lining resists corrosion and heat, so you can run strings of fire without the barrel giving up. It’s built for longevity, not bench racing.
• M-LOK Compatible Forend – WHY IT MATTERS: You can mount lights, grips, or bipods exactly where you need them, no proprietary junk. That’s modularity that works in the field.
• Flat Dark Earth Finish – WHY IT MATTERS: The ARID FDE coating hides mud, dust, and wear better than black. It’s a working man’s color that doesn’t show every scratch.
• Semi-Auto Action with Mil-Spec Trigger – WHY IT MATTERS: A standard trigger you can replace with any AR-15 drop-in if you want a lighter pull. No proprietary nonsense to lock you in.
• 30-Round Magazine Included – WHY IT MATTERS: Comes with one Magpul PMAG Gen M3, so you’re ready to load and shoot out of the box. No need to hunt for mags.

Who It’s For

This rifle is for ranchers, rural workers, and anyone who needs a reliable carbine for predator control, target practice, or truck gun duty. If you want a tool that runs without fuss and takes standard AR parts, this is it. Not for competition shooters chasing light triggers or race guns—this is a workhorse.

Pros and Cons

• Pros: Solid build quality, chrome-lined barrel for durability, M-LOK for accessory mounting, standard AR-15 compatibility, lightweight at 6.8 lbs.
• Cons: The mil-spec trigger is gritty out of the box—plan on a $100 upgrade to a Geissele or Timney if you want crisp breaks. Also, the 16-inch barrel is a compromise for close quarters; a 14.5-inch pinned model would handle better in tight spaces.

Comparison: Maxim MDX 516 vs. Zev Technologies OZ9 vs. Geissele Super Duty

Feature	Maxim MDX 516	Zev Technologies OZ9	Geissele Super Duty
Caliber	.223/5.56	9mm (pistol)	.223/5.56
Barrel Length	16″	4.5″	16″
Weight	6.8 lbs	1.8 lbs	7.2 lbs
Finish	Flat Dark Earth	Black	Black
Price	$2,425.50	$1,800	$2,100
Best For	Utility/ranch use	Concealed carry/pistol	Duty/tactical

FAQ

What is the barrel twist rate on the Maxim MDX 516?

The barrel has a 1:7 twist rate, which stabilizes heavier bullets like 62-grain and 77-grain loads. That’s standard for 5.56 NATO.

Does this rifle come with iron sights?

No, the MDX 516 ships without sights. It has a Picatinny rail on top for mounting optics. Plan on adding a red dot or scope.

Can I use standard AR-15 magazines in this rifle?

Yes, it takes any standard AR-15/M16 magazine. The included Magpul PMAG Gen M3 works with both .223 and 5.56.

Is the handguard free-floating?

Yes, the M-LOK forend is free-floating, which helps accuracy by not contacting the barrel. You can mount accessories without shifting zero.

Trust and Delivery

• ✓ Nationwide delivery (all 50 states)
• ✓ Ships 1-2 business days
• ✓ 30-day returns
• ✓ Secure checkout

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Last updated: April 2026