DS Arms ZM4 Enhanced 5.56mm | Gun Review

DS Arms’ ZM4 Enhanced is well built and well equipped thanks to its accuracy upgrades and Magpul standard equipment. Shown with an Aimpoint Patrol Rifle Optic.

The 16-inch barrel is capped with a CNC-machined Yankee Hill Machine Phantom muzzle brake installed on 1/2-28 threading.

The crisp, single-stage trigger weighed in at 7.5 pounds. DS Arms’ ambidextrous selector switch is a nice touch for left-handed officers.

The ZM4 Enhanced’s lower receiver, forged from 7075-T6 aluminum alloy, features a flared magazine well for faster reloads.

The Magpul MOE buttstock has a slim A-frame profile that avoids snagging and shields the release latch to prevent accidental activation.

DS Arms equips the ZM4 carbine with a forged front sight base with a bayonet lug.

The ZM4 Enhanced’s barrel has an M203 cutout as well as longitudinal flutes that increase its rigidity and help dissipate heat faster.

Magpul’s durable, polymer MOE vertical foregrip helps make the ZM4 Enhanced more controllable, especially during rapid-fire strings.

The Magpul MOE handguard helps keep barrel heat away from the shooter, and it’s complemented by DSA’s enhanced delta ring.

The forged upper and lower receivers on the test ZM4 carbine matched up very tightly—a quality that increases its inherent accuracy.

Any LE unit cruising around without some variation of an AR in the cabin rack or the trunk is an anomaly today. Knock off a couple of decades and the same would not be true, but two events changed everything: the North Hollywood shootout in 1997 and the 1986 Miami shootout between FBI agents and serial bank robbers Matix and Platt.

The latter incident did not have an immediate effect on the issuing of ARs to LEOs, but it did set the stage for changes in some attitudes regarding armament. Platt had used a rifle quite effectively against the FBI, which led administrators to move from revolvers to pistols—and left the door open for rifles in the future. The North Hollywood shootout showed that the time for patrol rifles had arrived.

The burgeoning popularity of the AR family of rifles in the non-commissioned and LE world has led to an equally burgeoning array of those making the now-ubiquitous AR in a multitude of variations. A huge percentage of those makers are established and know what they are doing, but a few are simply assembling their wares from any boxes of parts they can find. The latter is what happens in most home assemblies, which usually work fine, but a number of those are plagued by problems. Falling into the “know what they are doing” category is a company whose reputation was originally built not on the AR but the inestimable FAL—DS Arms.

At first blush, it may seem odd for an FAL company to be building ARs, but the knowledge DS Arms (DSA) acquired from manufacturing FALs translates quite well into building ARs. DSA is certainly not a one-trick pony, having parlayed its FAL empire into a company involved in producing the FAL and several other firearms groups, including the AR. I still own the first DS Arms FAL I tested many years ago, a testament to the quality of work the company does. This quality and know-how translates well into anything the folks at DS Arms undertake.

DSA currently offers nine versions of its AR-platform rifle, the ZM4. All but one are M4-pattern carbines, with the exception of a 20-inch-barreled, fixed-stock rifle. Nothing but American products are used in the manufacturing of each ZM4, which I guess makes it an American buy!

Gun Details
The ZM4 I received for testing, officially part number ZM4RCR16M4MK-A, also known as the ZM4 Enhanced flattop carbine, has several Magpul accessories that come standard. A number of manufacturers offer versions of their products sporting a single Magpul item or completely decked out in everything Magpul—and why not? Magpul products are some of the hottest and most-liked items in the land. Magpul’s primary source material is a tough, resilient polymer that stands up to daily abuse—the kind LEOs can easily dish out!

The heart of any AR is the quality and mating of the upper and lower receivers. The ZM4 upper and lower receivers, machined by DSA from 7075-T6 alloy forgings, are designed to mate perfectly with no play or jiggle, and then given a nice-looking Type 3 hardcoat anodizing. With receivers like this, you have an excellent base upon which to build a good rifle.

Completing the lower receiver is a Magpul MOE pistol grip and Magpul’s six-position MOE stock—both excellent choices—along with DSA’s ambidextrous safety selector switch. The mil-spec, single-stage trigger weighed in at a usable 7.5 pounds with a crisp break. The Magpul MOE grip feels great but does not cover the gap between it and the standard triggerguard; you’ll need Ergo’s “Gapper” to fill it.

The M4-type, flattop upper receiver has index or T-marks engraved into the cuts rather than being painted on. Why’s this important? Many paints do not resist cleaning solvents well. A Magpul MBUS flip-up rear sight, shown in a DSA website photo but not listed as standard equipment, came secured to the flattop rail on my test sample.

DSA’s AR barrels arrive with extensions in place rifled and chambered for 5.56mm NATO ammo. From there, DSA does the final machining, giving the barrel its contour. The ZM4 Enhanced’s 16-inch, M4-profile, 4140 chrome-moly barrel also features good-looking and functional flutes on the exposed portion. The rifle also features a DSA-produced forged front sight base with a bayonet lug, a Magpul MOE handguard and an MOE vertical foregrip. This 1-in-9-inch-twist, non-chrome-lined barrel has M4 feed ramps and evenly applied Parkerizing. The barrel is mounted to the receiver using DSA’s enhanced delta ring, which is shaped to blend with the Magpul MOE handguard. The muzzle is capped with an effective CNC-machined Yankee Hill Machine muzzle brake.

DSA’s forged and anodized 7075-T6 aluminum charging handle worked smoothly. The 9310 super-alloy-steel bolt, also manufactured by DSA, is magnetic-particle inspected and given a Parkerized finish. The bolt includes a hardened-steel extractor, a heavy-duty extractor spring, a black extractor insert, with mil-spec gas rings and O-ring. Everything is done right on the chrome-lined, Parkerized, M16-style, 8620 steel carrier, including being shot peened and having a staked, chrome-lined gas key. The entire bolt carrier is made of DSA-produced metal parts.

The ZM4 is wrapped up in a hard plastic box with one 30-round, blued D&H Industries magazine. For those who like things in a nutshell, all of the preceding boils down to one thing: DSA’s ZM4 rifles, including the Enhanced version, are excellent representatives of the family Eugene Stoner birthed—and that means they should make great law enforcement carbines as well. But all of that needs to be proven, doesn’t it?

Range Time
Proving a firearm’s worth is an enjoyable part of this job. DSA’s ZM4 Enhanced felt good in my hands, with the Magpul furniture as comfortable and ergonomic as expected. That would be tested with a few exercises, as time at the bench would prove the ZM4’s accuracy potential.

To leave nothing to chance, I equipped the ZM4 with two optics built with the AR family in mind, each designed for specific use from famed scope-maker Leupold. I chose them from the new Mark AR lineup, each at the opposite end of the spectrum—the Mark AR 6-18x40mm and the Mark AR MOD 1 1.5-4x20mm. Both scopes arrived with the Leupold FireDot reticle, which provides an illuminated dot in the center that draws the eye quickly, and external elevation- and windage-adjustment knobs. Finally, each scope was attached to the ZM4’s flattop using Leupold’s new, rock-solid Mark 8 Integrated Mounting System.

Despite heat that would make a leopard gecko pant, I managed to get all of the accuracy work out of the way in a single day, leaving succeeding range trips for tactical exercises. The ZM4’s accuracy was certainly on par with other carbines I have tested, with 100-yard, five-shot groups averaging between 1 and 1.3 inches. The best group of the day, measuring 0.92 inches, was produced with Hornady’s 55-grain TAP ammo. Of course, the accuracy demands of patrol officers, or most other officers equipped with ARs, will seldom extend to 100 yards, but it is nice to know that the DSA ZM4 can handle 100-yard and farther exceptions to the rule.

From the bench and during the range exercises, the ZM4 Enhanced displayed excellent reliability with each load tested. It also worked without a hitch as I fed it from a variety of polymer and metal magazines. All of this is important for shared carbines loaded with who knows what and fed by whichever magazine is available. The rifle’s handling and close-quarters performance was great, just as expected with an M4-type carbine. The 16-inch barrel and collapsible stock would make the package very handy in close quarters—halls, entryways, doorways, congested/cluttered rooms found in meth labs, etc. The Magpul forend and vertical foregrip were excellent for weapon control, and the smooth-operating stock was easy to adjust for a more precise shot or to fit different body sizes.

Final Thoughts
Even though the DSA carbine’s trigger pull was a little heavier than I might prefer, the crispness of the break helped to provide good accuracy. Truthfully, if this were a carbine shared between a number of officers, the trigger pull is exactly what is needed to avoid having errant rounds going off. As for the fluting on the ZM4’s barrel, I was shooting a plain-barreled carbine along with it, and it did seem that the fluting sped up the heat dissipation. I would need a digital thermometer to be sure.

Equipped with Magpul’s rugged furniture, reliable performance, a muzzle brake from YHM, barrel fluting and an MSRP of $929, I’d have to call this a great buy. Toss in DS Arms’ proven quality and all-American components and this really is a great deal for a department or personally owned rifle carried on duty! For more information, visit dsarms.com or call 847-277-7258.