The Ever Popular MK18 From Daniel Defense

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Daniel Defense’s Mk18, currently offered in three configurations (two pistol models and one SBR), is a firearm that grew out of USSOCOM’s SOPMOD CQBR program, and is the commercial version of the Mk18 Mod 1 currently in service with our troops. That’s a shocking number of military acronyms in one sentence, and for the full rundown of the military origin of this design (with even more acronyms!) check out the sidebar. I will say that this short-­barreled gun originally had a very narrow role with our military, but much like what happened with the M1 Carbine, other units saw the value in this compact rifle.

There are two pistol versions of the Daniel Defense Mk18, one which sports a LAW Tactical side-­folding adapater, and the standard model, a sample of which I obtained for testing. While being able to fold your stock/brace to the side for transport/storage is a neat feature, the LAW adapter adds weight, length, complexity, and cost to the design, plus moves it farther away from the looks of the original military Mk18, so I got a standard model to test. Apart from the lack of a stock and full-­auto capability, Daniel Defense tells me that their Mk18 pistol is otherwise identical to the Mk 18s they currently provide to the military.

There are two versions of this standard Mk18 pistol, the black version and the FDE version. You can tell I was sent the FDE version because the handguard is a light chocolate brown color … . Yeah, I’m not sure if Daniel Defense got the memo about what the color “Flat Dark Earth” is supposed to look like, as their FDE looks more like MCB (medium chocolate brown). The “FDE” version costs the same as the all-­black version, and I like the color contrast of the handguard against the receiver, so this is is the version I’d choose if I was buying it for myself (more on the color in a bit). I also had Daniel Defense include a set of their iron sights with the pistol, as they are so iconic and distinctive, but they are not standard with the pistol.

Breakdown of Features and Options

The Mk18 sports a 10.3-­inch barrel and a 5.56 NATO chamber. The barrel is chrome-­moly vanadium steel, cold hammer forged, with a 1:7 twist and a carbine-­length gas system. The barrel has a heavy phosphate coating, is HP/MPI tested, chrome-­lined, and meets all military specifications. The barrel has a “government profile”, which means it is medium weight/thickness.

The barrel is tipped with Daniel Defense’s proprietary flash suppressor, which is a bit longer than the standard A2. It has five slots and a solid bottom, and is constructed of 17-­4 PH stainless steel with a nitride coating for the utmost in durability. Like it should be in all serious use guns, the gas block is pinned in place. I had heard that Daniel Defense recently changed the gas port size on their Mk18 barrels. These guns are known to be a bit “overgassed” so they are guaranteed to run in all conditions, but that often results in more recoil, with a lot of gas blowing back into the faces of the people running them suppressed.

I checked with Daniel Defense, and was told, “Daniel Defense 10.3-­inch 5.56x45mm NATO barrels manufactured for the commercial market prior to June, 2017 have a 0.081-­inch gas port, which provides reliable operation with a variety of ammunition available on the commercial market. After an inline change in June, 2017, all 10.3-­inch 5.56 barrels transitioned to the Mil Spec 0.070-­inch gas port, identical to the products manufactured for the MILE (Military and LE) market.”

Daniel Defense RIS II Handgaurd

The barrel freefloats inside a handguard which is very distinctive. Daniel Defense’s RIS II (Rail Interface System II) is the current military spec handguard for the Mk18 rifle, and the version on this pistol is in every way identical. It is 9.5-­inches long, which means it reaches right to the start of the 1/2"x28 threads on the 10.3-­inch barrel, but not past, so you will have no clearance problems when mounting a suppressor.

On the top of the side rails you’ll see the patent number, NSN, and CAGE codes all laser-­etched. This is in part because DD supplies individual RIS II handguards to the military in addition to other parts, upper receiver assemblies, and complete guns. It is constructed of 6061 T6 aluminum. While a quad rail like this is very 2008 in appearance, about the only “bad” thing you can say about it is that it’s a bit wide under your hand (2.23 inches wide by 2.25 inches tall). This handguard is strong. Grab the barrel and the handguard together and squeeze, and it is the barrel that flexes. The rail was designed specifically to meet a request of SOCOM. The bottom section of the RIS II rail detaches so the user can freefloat attach an M203 grenade launcher without additional parts. It provides an uninterrupted upper rail, with the slots T-­marked, and has a Mil-­Spec Type III hard coat anodized finish.

I inquired as to the MCB (medium chocolate brown) look of the handguard, and the fact that only the handguard sports a color finish in the Mk18’s FDE version. My contact at Daniel Defense told me, “Only the rail is FDE because that is the way SOCOM runs their Mk18 SBR rifles. We supply SOCOM with all their RIS II FDE rails [Mk18 and M4A1] so we make all of our Mk18 pistols in that configuration, or just all black. “As for the color being closer to MCB, 
[yes, I actually threw Medium Chocolate Brown at Daniel Defense], it is because of the anodization process. It’s a chemical reaction and you only have so much control on how dark or light the color will come out. Every batch is different from the last and next as well because of this process.” In fact, there is no military specification for “FDE,” so you can easily find a dozen different shades of brown/tan that are all called Flat Dark Earth.

The handguard is held in place by six sizable bolts. The handguard is bolted to DD’s “bolt-­up” plate, which is installed between the upper receiver and the barrel nut. The bolt-­up plate has anti-­rotation tabs. The end result is very tough, and with all of the lightening holes in the handguard it is not nearly as heavy as it looks. Seriously. Total unloaded weight of this pistol is 5.85 pounds, and with the iron sights and rubber rail covers in place the total weight of my sample was still just six pounds, one ounce. Center of gravity with the SBA3 brace fully extended is in the middle of the magazine well.

Daniel Defense sends this pistol out with three rubber rail covers to protect your hands — excuse me, not rubber but “Santoprene,” which is heat-­resistant to 300°. I tried shooting the pistol both with and without them, wondering if the rail would feel better bare. Even though the bare rail was slightly narrower, the difference was barely discernable under my hand, and I actually preferred shooting the gun with the rail covers in place. As for accessories, half the things meant to mount on handguards these days are still designed to mount directly to rails. So you don’t have to bother with installing a rail in your M-­LOK slots, you’re already there.

The upper and lower receiver are Mil-­Spec forged 7075 T6 aluminum. The upper receiver has M4 feed ramps. You might also spot that the ejection port cover is not metal but instead polymer. This is somewhat new for Daniel Defense, and I asked about it. I was told, “The upgraded polymer ejection port cover provides a better seal, won’t rust, can’t be bent to interfere with the function of the rifle, and is about the 1/3rd of the weight when compared to traditional steel ejection port covers.” On the left side of the upper receiver, etched in white, you’ll find MK18. Forward of that is 5.56, in white and inside a bullet pictogram. I’m guessing the military guns don’t have the white markings, but that’s a cosmetic difference, not a functional one.

Components of Mk18 

I’ve written up Daniel Defense rifles and pistols before, and one of the few complaints I consistently had was the inclusion of basic, G.I.-­style charging handles in what are not inexpensive guns. However, it’s been a few years, and I am happy to see that DD has now designed an improved charging handle and is including it in their guns, including the Mk18.

Daniel Defense’s Grip-­N-­Rip charging handle is ambidextrous and seems built quite robustly. Not only does it provide a larger gripping area, it is specifically engineered to vent gas away from the shooter’s face during suppressed fire. I watched a YouTuber stumbling through a review of this gun, mentioning how the new charging handle vents gases, and then he admitted “I don’t know how it does that.” as he is holding the gun so the camera can clearly see the vent hole in the right side of the charging handle … .

Yes, on the right side of the charging handle, on the most forward part of the body as it sits in the receiver, you’ll see a round hole where the gases vent outward and not into the shooter’s face. There’s a hole on the left side as well, it’s just hidden under the locking lever. This charging handle also features a curving ridge on the top center of the charging handle meant to redirect those gases as well — this little trick was pioneered by PRI close to two decades ago with their Gas Buster charging handle. I guess with YouTube you get what you pay for.

The bolt carrier group meets all military specifications and has the DD logo etched on the right side of the carrier, visible through the ejection port. While this is a commercial gun, it is built to military specs — you’ll see a chrome-­lined carrier, properly staked gas key, even a castle nut that has been staked in two places. At the back of the receiver you’ll see the end plate has a QD sling socket, a simple but very functional extra I’ve really come to appreciate. An H (heavy) buffer is installed in the gun.

The lower receiver looks like a standard forged Mil-­Spec design. It wasn’t until I was reading the specs for this pistol that I saw it came equipped with a “enhanced flared magazine well.” While the external dimensions of the magazine well are not changed from Mil-­Spec, flipping the pistol over I did see there is a more pronounced bevel to the magazine well.

This pistol ships with one of Daniel Defense’s 32-­round polymer magazines. This magazine has an anti-­tilt follower and comes standard with a bit of a pull tab on the basepad. DD likes to say this magazine is the same size as a standard magazine, but in fact it’s a bit larger (about a quarter inch before you add the tab length). They shorten the height of the follower and reduce the number of coils in the spring to make room for the extra two rounds. I haven’t used DD mags a lot, but I’ve never had a problem with them.

The pistol grip is a Daniel Defense design with rubber overmolding. It is one piece with the oversize polymer trigger guard and has an internal water-­resistant storage compartment. It has a slightly more vertical angle than a standard A2 grip. The “arrow tread” pattern on the grip matches that of the rail covers. This pistol also sports an “ambidextrous” (bilateral) selector lever. While the right-­side lever on their similar DDM4 V7 is a bit reduced in size, the right-­side lever on the Mk18 is the same size as the lever on the left side. Which means I hate it, because it hits my trigger finger every time I rotate the selector lever from Safe to Fire. As a rule, I hate all ambi selectors on ARs for exactly this reason, but at least single-­sided replacements are inexpensive and easy to install.

Other than the G.I.-­spec charging handle, one common complaint I’ve had with other Daniel Defense ARs is their use of GI-­type triggers in what are arguably very expensive guns. Note I didn’t write G.I. triggers but rather “G.I.-­type,” as there is no military specification for a semi-­auto AR/M4 etc. trigger group. In other models, a heavy gritty GI-­style trigger pull just seems a bad idea, however I don’t have an issue with it (at least philosophically) in the Mk18. This is supposed to be the commercial version of a military gun, so having a military-­style trigger pull only seems right, thematically. That said, a gritty seven-­pound trigger pull is not conducive to accuracy, so it would be the first thing I would change (probably to a Geissele) were I to buy this piece.

Iron Sights and Optics

As I mentioned, the Daniel Defense “Rock and Lock” fixed iron sights are distinctive, and very well known. They are machined from aluminum, with MilSpec steel internal parts (post, apertures, etc.). They are built tough but their aluminum bodies are hollowed out, so the two sights together only add 2.8 ounces to the weight of your gun. A lot of people run a fixed DD front sight with a folding rear, much like they have tall iron sights on a handgun equipped with a red dot — that front sight post helps keep your eye centered in the window of your optic window.

I couldn’t wait for the 1.93-­inch Geissele Super Duty red dot mount to arrive, so my first trip to the range was a shakedown of the pistol using old fashioned iron sights. The DD iron sights provide a 14.75-­inch sight radius, roughly the same length as found on a standard CAR-­15/M4. I zeroed the iron sights at 25 yards and was once again reminded why people like red dots — they’re much simpler and faster.

The military only uses 5.56 NATO ammunition, which is loaded to higher pressure than commercial .223 Remington ammunition. With them going to a smaller (0.070 of an inch) gas port on their commercial barrels, I was curious if I could induce a malfunction shooting soft .223 ammo. I zeroed the pistol with American Eagle 5.56 NATO M855 (62-­grain green tip) and then fed it Frontier and Wolf .223 Remington ammunition. Wolf steel-­cased ammo in particular is known to be very soft, and I could definitely feel the difference in recoil between the 5.56 and .223 ammo, but the pistol ate 75 rounds of 5.56 and 100 rounds of .223 that first outing without a hitch. I used the DD magazine as well as a Lancer L5 AWM and 2nd and 3rd generation Magpul PMags.

One good thing about a handguard that is both wider and thicker than the average is it takes substantially longer to heat up during extended strings of fire. If you’re talking a standard “combat” load of five 30-­round magazines, with the RIS II chances are you’ll be out of ammo before the handguard gets too hot to hold. I was shooting in 22-­degree weather and wearing leather gloves, so even when burning through three magazines in five minutes the handguard barely got warm enough for me to feel it. FYI: that’s 22° Fahrenheit, not Celsius. There are two kinds of countries in the world, those who use the metric system and those who have landed on the moon.

I like the DD “Rock and Lock” iron sights and red dots, but not the combination together. The DD iron sights set the red dot at co-­witness height, which might be workable with a big-­windowed sight like an EOTech, but when using just about any other red dot clutters the view so much you’ll have trouble finding the dot. Can’t see the forest for the trees, and all that.

To both have my cake and eat it too, I kept the DD sights in place and mounted the (relatively new) Trijicon MRO HD red dot in a tall (1.93 inches) Super Precision mount from Geissele. This puts the dot itself 1.93 inches above the rail, which places the optic just above the height of the iron sights, so your view is not obstructed. If you decide to run night vision or are wearing some kind of mask (i.e. SWAT guys in gas masks) this taller height still allows you to acquire the red dot.

The MRO has been around for a while and has been very successful. With the wider objective lens, you do not get a tube effect at all and in fact the field of view is so wide I could see the top half of the front sight tower. The HD version offers the dot of the standard MRO, or you can switch to a circle/dot reticle, pairing a 2 MOA dot with a 68 MOA ring. With some narrow tube sights, I find a circle/dot reticle to be too much, cluttering up the field of view. With the MRO’s open design, I found I really liked the circle/dot reticle. Expect a more detailed review of this optic in a later issue, but it worked great during testing of this pistol.

Range Report

While I did the requisite accuracy work for the accompanying chart, this isn’t a benchrest gun, this is a pistol version of specialty SBR dreamed up during the height of our War on Terror, purpose-­built for use in and around vehicles and in urban environments at high speed — that’s why I prominently featured one in my 2020 not-­quite-­as-­fiction-­as-­it-­used-­to-­be modern civil war novel Dogsoldiers, set in Detroit (where else?).

On three separate range trips, I kept warm with the Mk18, running between cover and engaging various paper targets, practicing my snap sight pictures, and working the Mk18 off a rifle barricade. Its abbreviated length makes it quite maneuverable, and the balance is just right. For as short as it is the Mk18 is not as loud as you might expect, because it doesn’t have a muzzle brake, and recoil is more straight back than it is up. The Trijicon MRO HD was great in speed drills, only thing that slowed me down was the gritty/heavy trigger.

Short barrels, because they are stiffer, are inherently more accurate than longer barrels, so don’t think because it’s a “pistol” it won’t group. However, hindering my accuracy testing was the gritty seven-­pound trigger. Equipped with a crisper lighter trigger I feel confident that I could have reduced my groups somewhere between a little and a lot. That said, you have to remember that this is, at heart, a military gun. Its bore is chrome-­plated for durability, but chrome-­plated bores as a rule are less accurate. Still, with ammo it liked and me dragging the trigger through gravel this stubby little gun would do under two MOA.

While this is technically “just” a commercial pistol, the military DNA in it is obvious even before you learn that, apart from the brace-­for-­stock and lack of full-­auto capability this piece is identical to the Mk18s supplied to our military. During testing I started thinking of the Mk18 (both in form and concept) as a tough-­as-­nails “baby battle rifle,” and even in semi-­auto pistol form it lives up to its military origin.

Daniel Defense didn’t invent the Mk18 but they now seem to be more associated with the model than anybody else, at least on the commercial side. I checked with them in regards to their military sales beyond simply the specced RIS II handguard. I was told, “Daniel Defense supplies complete Mk18 firearms as well as complete upper receiver groups, RIS II handguards, as well as a large quantity of our cold hammer forged barrels, parts kits, and accessories for upgrading existing military equipment. Various other Special Units/Other Government Agencies buy a wide variety of Daniel Defense products depending on their mission requirements. Currently, the only difference between the commercial guns and the ones supplied to the military would be full-­auto versus semi-­auto, unless the customer specifies another requirement.”

James Tarr is a longtime contributor to Firearms News and other firearms publications. He is also the author of several books, including CARNIVORE, which was featured on The O’Reilly Factor. Check out his latest novels at his website, OfficialJamesTarr.com 

Mk18 PISTOL SPECIFICATIONS

• Caliber: 5.56 NATO
• Weight: 5 lb. 15 oz. empty
• Overall Length: 28.75 inches (brace extended) 26.25 inches (brace closed)
• Receiver: Forged aluminum
• Barrel: 10.3 in. CHF, CMV, chrome lined, 1:7 twist
• Muzzle Device: Daniel Defense flash hider
• Brace: SB Tactical SBA3
• Pistol Grip: Daniel Defense with internal compartment and trigger guard
• Forend: DD 9.5 in. RIS II handguard
• Trigger: 7.0 pounds (as tested)
• Sights: None
• Accessories: One 32-­ round Daniel Defense magazine, lockable hard case
• MSRP: $1,967 ($2,101 as tested with iron sights)
• Manufacturer: Daniel Defense DanielDefense.com

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