Parvusimperator Reviews the LMT MARS-L

It’s no secret that I’m not a fan of bullpups. I don’t think that shorter overall length is worth all of the other compromises you get with bullpups, like awkward reloading and godawful triggers and no place to put accessories. I am also a huge fan of the AR-15 platform, so when the New Zealand Defence Force picked a direct-impingement AR-15 in the LMT MARS-L to replace their Steyr Augs, I was thrilled. Ecstatic even. This is also a victory for direct impingement over op-rod systems. It was a very good day. Let’s take a closer look at the MARS and see what improvements LMT has made.

The MARS-L is an offshoot of the CQB16. The biggest changes to the stock CQB16 are in the lower, which is now totally ambidextrous. Ambi safeties are easy to do, you just add a lever on the right side. With a little bit of work with a lever and cam, you can get an ambi mag release without too much trouble. The ambi bolt release requires a bit of extra work to the receiver, and there are a handful of companies out there who will make one for you, including LMT, Knight’s Armament, and Mega Arms.1 The changes are relatively minor, and while they add a couple machining steps and small parts to complete final assembly of the lower, it doesn’t substantively change any of the interfacing parts, so you can add any old upper to the ‘ambified’ lower.

In terms of the rest of the lower, it’s pretty simple. It uses LMT’s SOPMOD-pattern stock, which is an excellent choice. Most pictures I’ve seen also come with an ‘ergo grip’ which is a much better choice than the lame A2-pattern pistol grip. I’m not sure if that’s what’s being delivered to New Zealand though, or if that’s just on the display models because that’s what LMT usually uses on the rifles they build for guys like me. The trigger group is safe/semi/full auto.

The upper has a few differences from a regular M4. The most obvious is LMT’s monolithic upper. The picatinny quadrail handguard and upper receiver are one piece of aluminum, which is clearly stronger than having two separate pieces. It also looks cool, and means you never have to worry about sights getting jacked up because your handguard got knocked around or sucks. The barrel is held in place by a pair of torx screws, which makes barrel changes easy. Not that this is a big deal for most troops, but it’s still pretty cool. It does lock you in a lot more to picatinny rail interfaces on your accessories, but that’s not a bad thing. That interface isn’t going anywhere for a while–it’s got a ton of momentum and lock-in from being around for a while. A lot like the 5.56 round. Note that the regular grunts get a CQB-length (9″) handguard, and the special forces guys get a longer (12″) one. The regular grunt version has a bayonet lug mounted on the right side of the barrel. This way, it doesn’t get in the way of a grenade launcher mounted under the barrel on the quadrail.

While in the civilian world, Picatinny rails aren’t the most popular thing, and quadrails are decidedly old-school, for the military they’re still the right choice. They have lots of picatinny-rail accessories in the system already. Many of these do not have Mlok or Keymod versions, so adapters would be required. Which gets you back a bunch of weight that you got rid of by going to Mlok/Keymod. Plus, you can’t get rid of picatinny rails entirely, because optics mount to *those*. Mlok and Keymod aren’t designed to let optics retain zero after mounting/dismounting. And you can’t get a receiver with those. Plus, you can get a 40 mm grenade launcher to attach to quadrails. No such luck for Keymod or Mlok. So why bother with a bunch of redundant attachment methods. Suck up a bit of weight, and stick to quadrails, if you’re an army.

Internally, it’s got the LMT improved bolt. The Special Ops one has the LMT improved bolt carrier. I’ve already talked about these2, so I’ll just summarize and say that they are redesigned a bit to improve the life of these small parts. I like the design. Anyway, you might be wondering why not an op-rod AR design? There are a lot of those out there, and lots of people seem to like them. And that’s basically what the HK 416 is. But it doesn’t really get you anything, and it has its own downsides. Most of the HK 416’s ability to take sustained fire longer is due to the heavy barrel profile. Colt can get you almost the same thing for less trouble on your AR-15 with the SOCOM-pattern barrel used on the M4A1. More barrel, more fire. And LMT does not use lightweight barrels on their builds.

The op-rod is a conversion, and it adds issues in that you’re applying forces in ways the bolt carrier wasn’t designed to take, so it can tilt and have issues with wear. Also, the op-rod adds weight. The direct impingement system puts the ‘piston’ bit inside the bolt carrier, so there’s no op-rod to deal with. Which means no op-rod weight. Even if you’re concerned about the gas tube melting, you can beef that up a bit and still come out way ahead in the weight department. Adding an op-rod to an AR is a solution in search of a problem. Not that op-rods are bad, just design the gun from the ground up around the operating system. Like you should. Or just crib from the AR-18 design like everyone else.

But enough about technical gun engineering discussions. What does this give the Kiwis that they don’t have with their AUGs. Well, it’s replacing the Aug A1, which had a fixed 1.5x optic. This was revolutionary in the 70s when the Aug was introduced, but it’s eclipsed now by much more capable optics. The MARS can accommodate the fancy optics of today and tomorrow with it’s rail interface for adding sights. It also can mount (and comes standard with) folding backup iron sights, which is piece of mind.

Further, the conventional layout means that in recent urban warfare engagements, you can switch shoulders to take opposite corners at will without eating brass. Plus, you get a better trigger, and although we’re not talking match triggers here, godawful triggers make for politically embarrassing hits on bystanders. Just look at the NYPD’s 12 lbs pull weight triggers on their Glocks.

One more thing comes to mind, and this one isn’t thought of a lot, probably because most people don’t shoot very much. If your gun hasn’t malfunctioned, you haven’t shot it enough. Fact. And, because of where the bullpup action is, and how sealed up it has to be to keep your face safe, when a bullpup malfunctions, clearing it is a massive pain. Tearing a weapon apart on the range sucks because you’re always losing things. Have fun doing it under fire.

It’s nice to have a real-world military agree with you. Go Kiwis! Say, the MARS-L looks an awful lot like the rifle I specced out for issue.

This is the best 5.56 service carbine around, bar none. Better than the SCAR, better than the G-36, better than a regular M4, better than any lame-ass bullpup, even better than the 416. Better than the XM-8 if that was still a thing. Sorry HK. We’d take them in a heartbeat. Specifically, the regular infantry version, with the bayonet lug and shorter handguard, but we’d specify that enhanced carrier.

1.) Check out my build notes here.
2.) See my Milspec Challenge article

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