Tag Archives: militariana

Resurrected Weapons: XM307

Here’s yet another attempt to replace the Mk. 19 GPMG and/or the venerable M2 HMG. The XM307 was part of the same program that gave us the XM29 OICW, and later the XM25 once the OICW failed. The program itself emerged from a 1980s study saying that weapons development had reached a plateau, and that the next breakthrough would come with the integration of airburst-fused high explosives into the US Army’s weapons. They had tried to schedule a breakthrough in the late 1960s with SPIW. They failed. Now, a new generation of engineers would try their hand.

The XM307, or Advanced Crew Served Weapon (ACSW), had the same airburst principles as the XM25 and XM29. The gunner would use an integrated fire control system to get the range to target with a laser rangefinder, set an airburst distance, and then shoot rounds at the target. Except now with automatic fire. Let’s look at a quick size comparison chart:

XM307M2Mk. 19
barrel length25.1″45.0″16.25″
weight50 lbs.83.78 lbs.77.6 lbs.

It’s definitely lighter. Plus, it’ll bring a flatter trajectory than the 40mm grenades of the Mk. 19, so it should be easier to score hits with. Those are pluses. And, the M2 doesn’t pack an explosive punch. All good things so far for the XM307. So let’s talk lethality.

From autocannons, we know that autocannon ammunition makers don’t think a 25mm autocannon shell holds enough explosives to make an airburst fuse option worthwhile. We know there are lots of deployed 25mm systems, so there’s plenty of incentive to try. Big market, but nobody’s bothered. This isn’t a perfect comparison, of course. Sizes may vary, but if there’s a difference, the autocannon has the bigger projectile. A 40mm Bofors fires a much bigger round than the 40mm Mk. 19. Still, it’s cause for concern.

More concern comes from the test deployment of the XM25. In Afghanistan, while there are plenty of accounts of airburst rounds scaring Taliban fighters away, there are no accounts of it actually killing anyone. And this should be its best chance for success: taliban fighters don’t wear any kind of protective gear. None. If it can’t get kills there, what about when it encounters troops wearing actual modern armor? At least the Mk. 19 has a long history of being effective against unarmored opponents. It starts somewhere. Also note that lots of comparisons with 40mm grenades make a comparison between 25mm Airburst HE-Frag and 40mm HEDP, which is going to be less effective in the pure-antipersonnel role than 40mm HE/HE-Frag.

Now, the XM307 has automatic fire capability, and a belt feed, unlike the XM25. We’re not limited to a one round for one round comparison, which means we’re going to get into “stowed kills” type computations. Clearly, the XM307 holds more grenades in a box than the Mk. 19, so we can try to come up with some notion of relative effectiveness. Or we could, if we had a lot of ammo and a proving ground. Unfortunately I don’t, and I don’t know if the US Army tried this computation. The XM307 was cancelled in 2007.

Another obvious option is to integrate the airburst fusing and targeting system into existing 40x53mm grenade systems. So you’d still have the option of using existing grenades that work, plus you wouldn’t have to develop an entirely new round and ammo system. Someone at DoD actually thought of this, and the Mk. 47 was born. It’s lighter than the Mk. 19, fires the same 40x53mm grenades, and is equipped with a targeting system to set the fuses of airburst grenades. In US Service, that would be the Mk. 285. It’s in limited use in the US Military, and has seen export success with Israel and Australia. So let’s go with that, because it’s way less cost and risk.

Verdict: Funding Denied by the Borgundy War Department Ordnance Procurement Board

Resurrected Weapons: The LWMMG

Around 2010, General Dynamics independently1 developed what they called the Lightweight Medium Machine Gun. This weapon was designed to fill the “capability gap” between the M240/MAG-58 GPMG, chambered for 7.62x51mm and the M2 Heavy machine gun, chambered for 12.7x99mm. The idea was to be able to “overmatch” enemy PKMs in a weapon that was still man-portable like an M240.

The cartridge chosen was the .338 Norma Magnum2. This cartridge was designed to fire the excellent 300 grain HPBT .338 projectiles from rifles that had actions too short to accept the .338 Lapua Magnum cartridge. It was chosen for this application for its excellent ballistic performance at range, to really allow the LWMMG to stretch it’s legs.

Clearly, the .338 Norma Magnum has a lot more recoil energy than the 7.62x51mm round used in the M240. But General Dynamics wanted to maintain portability, and their goal was to maintain the “footprint” of the M240. So it couldn’t be too much heavier or larger. To accomplish this, General Dynamics used the same recoil system they had developed for the XM806. Having the barrel, gas system, and bolt recoil together meant they could distribute recoil forces easier, and not have to use as much weapon mass to do so. The LWMMG ended up being able to use the same tripods as the M240, and is three pounds lighter than the US Army standard M240B. Later versions of the LWMMG cut two more pounds off the weight.

The US Military opted not to procure the weapon, and I don’t really blame them. While the weapon is about the same weight as the current GPMG, the ammo is heavier, round-for-round. And, frankly, the extra range over 7.62×51 is usually wasted, because of line of sight considerations or target discrimination considerations. If you are in PKM range, he is in M240 range. Or range of vehicle weapons. Or mortar range. There are lots of other ways to deal with that sort of opponent. And you’d be adding another round type and spares type to the logistics trail. The use of other weapon systems is an even better idea if the enemy comes with modern body armor.

Let’s get some numbers on the ammo weight side, since this ends up being pretty significant. We’ll look at the weight of 100 linked rounds of 7.62×51, .338 Norma Magnum, and .50 BMG. 100 rounds isn’t a basic load, but it’s a nice round number to work with. Your basic load/vehicle load will probably be some multiple of that.

  • 7.62x51mm NATO — 6.625 lbs.
  • .338 Norma Magnum — 12 lbs.
  • 12.7x99mm BMG — 29 lbs.

Can it replace other weapons? I wouldn’t use it to replace existing 7.62x51mm GPMGs, because of ammo considerations and because that range is really not needed in general. It’s wasted on the regular infantry and the training and optics available to them, plus it’s almost twice as heavy. The .338 Norma Magnum round is also entirely too powerful for a semiautomatic or select-fire Marksman’s rifle, so 7.62x51mm would stay in the inventory. The LWMMG also isn’t going to replace the M2, because you’re giving up some range and a lot of soft target terminal performance with the smaller, lighter round. To be fair, General Dynamics never proposed it as such. It’s a marvelous technical solution in search of a problem. Cool, but I’d rather spend the money on other things.

Verdict: Funding Denied by the Borgundy War Department Army Ordnance Board

  1. I.e. without a solicitation or RFP from the DoD 
  2. Not to be confused with .338 Lapua Magnum, which is a bit longer. 

Red Flag 18-1 Kickoff

It is on like Donkey Kong.

This year’s first iteration of the USAF’s aerial war games, Red Flag, kicks off today. There will be day and night exercises. There will be tons of the best simulated combat we can set up. Two things make this year’s Red Flag a little different than most.

First, the guest list. Red Flag is always an invitation only affair. For this one, it’s Diamond Super Platinum members only. Which means Australia and the UK, in addition to America. That’s it. Nobody else.

Pretty hardcore, right? You may be wondering why. There’s likely going to be some testing of sensitive capabilities. Also, let’s look at some interesting notifications for aircraft operating in Los Angeles Center airspace and flying in and out of airports in the Las Vegas area.

Arrivals and departures from airports within the Las Vegas area may be issued non-Rnav re-routes with the possibility of increased traffic disruption near LAS requiring airborne re-routes to the south and east of the affected area. Aircraft operating in Los Angeles (ZLA) center airspace may experience navigational disruption, including suspension of Descend-via and Climb-via procedures. Non-Rnav SIDs and STARs may be issued within ZLA airspace in the event of increased navigational disruption. Crews should expect the possibility of airborne mile-in-trail and departure mile-in-trail traffic management initiatives.


Among other things, the US DoD is cranking up a bunch of high powered GPS jammers in the Nevada Test and Training Range, and this might interfere with nearby civilian traffic. Consider yourself warned.

It’s about time we did some training in a no-GPS environment. See how we cope and develop TTPs. That’s what Red Flag is for.

Resurrected Weapons: XM806 Heavy Machine Gun

The Browning M2 is nearly 100 years old, and it is still a very effective weapon. It is heavy and made with decidedly old-school manufacturing techniques. The XM806 was an effort to replace it with a newer, lighter machine gun, still chambered for the classic 12.7×99 mm BMG round. The XM806 was a development of the cancelled XM312, which was a prospective heavy machine gun that could be easily converted to fire 25×59 mm airburst grenades.

The XM806 preserved the recoil system of the XM312 (and its grenade launching sibling, the XM307). This system had the barrel and bolt move forward when the trigger is depressed, forcing recoil forces to overcome the forward momentum of both the bolt and barrel.

The XM806 weighs only 40 lbs (18 kg), less than half the weight of the M2. It has less recoil than the M2, and it’s also easier to disassemble. On the other side, it has about half the rate of fire of the M2. For present uses, a reduced rate of fire probably isn’t a huge deal. We’re long past the days of expecting a heavy machine gun to be an effective antiaircraft gun.

While the weight savings are eye-popping, one might question the point. 40 lbs is still too heavy to easily manpack, and the weapon is still very bulky. And 12.7mm BMG ammo is big and heavy. It’s going to be a bother for a team of light infantry to deploy, and they’re probably going to be better off with GPMGs supplemented by antitank weapons, not least because of the weight of the ammo. As for vehicles, the difference between 40 and 84 lbs is basically immaterial. We can mount M2s on dune buggies. We can mount M2s on aircraft and helicopters. The weight savings really don’t get us much in terms of more usability in the roles that we normally find ourselves using a heavy machine gun. And (again) we still have the weight and bulk of ammo to deal with either way, which is a much more significant issue for small vehicles.

Probably a depressing way to look at it. But the biggest thing here would be cost, and it’s really hard to compete with an established system. When the US Army cancelled the project, they diverted funds into improving the venerable M2, and I can’t fault them for it. At least the XM312 added a new capability.

Verdict: Funding Denied by the Borgundy Army Ordnance Development Board.

A Cruiser By Any Other Name

I’ve discussed before that the Arleigh Burke-class is the best destroyer afloat today. It’s got a good radar, plenty of missile capacity, and comes at a pretty reasonable price due to its large production run. Competitors like the Daring class cost entirely too much and deliver entirely too little. Let’s look at a a follow on. Nothing lasts forever, and something newer, with newer systems, will be fun to sketch. This will be my version of something like the Zumwalt class. Though, because I prefer things evolutionary, it will be rather less ambitious. Admiral Zumwalt would have wanted it that way, anyway.

We’re not going to compete directly with the Burkes in terms of size, because that makes it really hard to justify the changes. And we’ve already sketched smaller. In case the title didn’t give the game up, we’re going bigger.

As always, we must first define our mission. Being a large cruiser, we’d like it to focus on air defense and air control, with plenty of land attack capability (i.e. plenty of missile tubes). We’d also like reasonable antiship capability and some antisubmarine capability, though this last is negotiable. I’ll pencil in some nice, off-the-shelf sonar systems now, with the understanding that designers can make adjustments as needed for cost reasons there.

On to the sketch! First thing to do is to forget about the stealth nonsense baked into the DDG-1000 design. Some low-observability features are a good thing, but the excessive stealth optimization of the Zumwalts with their special superstructure and ridiculous tumblehome hull is silly. A more normal hull design, bow raked forward, has far better seakeeping, and that’s much more important. Not only is it a patently obvious ship if one bothers to look out their windows, but we’d expect it to be able to handle Air Defense and Air Control, which means the radars have to be on, which means it will be pumping out electrons like the Las Vegas strip. And if we don’t turn on the radars, what exactly is protecting the carriers? Accepting that not every new design has to be a ghost’s shadow will help keep costs down. We need to limit the use of new technologies in new designs so the costs don’t explode. Nobody bats 1,000 with new designs. Some will fail, and we need to be resilient about this. Also, a more conservative design means we’ll be able to reuse some things from existing designs. Or, test out some new stuff elsewhere. Like we used to.

There you have it. Some gentle angles, avoid corner reflectors, keep the nice clipper bow. As a side effect, that’s a lot prettier.

Next: radars. I really like the original, un-neutered suite planned for the Zumwalts, namely the SPY-3 and the SPY-4. The SPY-3 is an X-band AESA radar, optimized for best tracking accuracy. The SPY-4, deleted from the DDG-1000s to save costs and still fitted on the Ford-class Carriers, is an S-band AESA radar optimized for high volume search. This split of functionality mirrors what NATO testing found to be best in the late 90s. These were integrated into a dual-band array system, which is some pretty revolutionary stuff. I’m fine with that as one of the key new technologies embarked, though the emitters could also be separated. The overall concept is right though. And, of course Aegis-type integrated fire control and combat management systems.

As a bonus, from an emissions perspective, a cruiser with a dual band radar looks a lot like a carrier with a dual band radar. Or maybe that other contact is another cruiser and the carrier is somewhere else. Or has its radars off. Emissions doesn’t tell you. With the right ECM and radar signature management, your active radar won’t help you either at range. Better go look, and hope you can radio your buddies back before you eat a missile.

On to missiles, and the tubes that launch them. The Mk. 57 can handle a greater volume of exhaust gasses than the Mk. 41, but the sheer number of deployed Mk. 41 tubes means missiles will be developed for that. Also, while the Mk. 57 is a bigger tube, it’s not much bigger, and there’s no missile around that would not fit in a Mk. 41 but would fit in a Mk. 57. Plus, the Mk. 57 modules are rather bulkier than those of the Mk. 41. So Mk. 41 it is! And we’d like to pack her with missiles. To hell with 80 missiles on nearly 15,000 tons. If we can’t do better than the 128 cells of a Ticonderoga, we should go home. Ideally we’d fit four of the big 64-missile clusters off the Ticonderogas for a total of 256 missile tubes. This gives us plenty of space for SAMs, including ballistic missile defense capable ones, LRASMs, Tomahawks, and VL-ASROCs.

Now, let’s talk about the gun. DDG-1000 originally had an ambitious vertical gun with guided shells, but this was shelved. The impact of development costs remains on the final design. I am not sold at all on ambitious gun projects that aren’t railguns, and those are nowhere near ready. The best estimates on the range of the Advanced Gun System put the ships entirely too close to shore. I’m fine with 155 mm, but 155 mm without being able to share shells (and shell development projects) with the army is patently absurd. And I’m still not entirely sold on the need these days, given how many other options there are for getting firepower on the beach, and how nasty coastal defenses can be. For my design, I’m quite satisfied with the 127mm/64 LW gun from Oto Melara. 127mm is a pretty standard naval gun caliber, and there are plenty of guided shells in that caliber under development.

There’s no need for extra antiship missile launchers given plenty of VLS cells and LRASM, so we don’t need to worry about those.

Point defense duties will be handled by at least two Rolling Airframe Missile launchers, mounted, well, wherever there’s room. Possibly amidships. Possibly fore and aft, which is rather more traditional.

Since we’re not obsessing over stealth, we can throw in some remote weapons stations and pintle mounted heavy machine guns to hose down any suicide bombers. Who will have no trouble finding a stealth boat because they use their eyeballs, not radar.

For propulsion, we’re going to go for Integrated Electric Propulsion, which has also been done on the Zumwalts. And could have been tested somewhere else. There’s no reason why it should be hard. Generators are run by diesel engines and gas turbines, and electric motors drive the screws. I’d like to take some time on a demonstrator to explore steerable propulsion pods for the electric motors in a military context, specifically focusing on cost, agility, and noise.

Helicopter fit is the usual hangar for two SH-60-size birds and beartrap-equipped deck. No reason to change it. Though, given the size, we should probably expand the hangar a bit to accommodate several drones.

Antisubmarine warfare is not our focus, but we should make a bit of effort to be prepared. A nice bow sonar and variable-depth towed array will do nicely, as will the usual pair of triple 325mm torpedo tubes amidships. Something like the Thales UMS 4110 CL sonar for the bow and a Captas 4 in the towed role.


The Component Advanced Technology Test Bed was another late 80s American test program to investigate new systems for future tanks. As we’ll see, it looked quite a bit different from the TTB, and where the TTB was testing a very specific change (namely the unmanned, low profile turret) the CATTB tested a variety of new technologies in a more conventional layout.


CATTB shared an Abrams hull, but the turret was new, and came with a bustle-mounted autoloader. The autoloader was very similar to the one on the Leclerc or K2. A new gun was tested, the XM291, which came in both 120 mm and 140 mm versions. The 120 mm version provided a lower-risk alternative to the 140 mm. The turret had rather large forward armor arrays, plus reasonably thick side arrays and a decent amount of roof protection. And I have no idea why they decided to mount so many smoke grenade launchers on there, but they did. This was before the advent of soft-kill active protection systems, but might not go amiss on a tank today with the right cueing system.

CATTB Rear view

As you can see from this rear view, the CATTB also came with a new engine: the XAP-1000 diesel. The Cummins/Allison XAP-1000 was based on the advanced Cummins XAV-28 V-12 diesel, a low-heat rejection engine. It used only oil coolant and has no water in the cooling system at all. Higher temperature exhaust gasses were tapped to run the APU. I don’t know a ton about this engine, but the US Army has a history of backing highly advanced diesel engines that end up being problematic. I would suspect similar things with the XAP-1000. Again, the project went nowhere. Later in the 90s, the Abrams was going to get a new engine as an offshoot of the Crusader project, but the proposed engine was not the XAP-1000. Instead, a gas turbine was chosen.

CATTB is a lot more of a conventionally designed tank. I do really like its lines. The project which was supposed to lead to the Block III MBT ended up leading nowhere due to changing priorities. Though, it is not at a museum. It is in the long term storage section of the Sierra Army Depot in Hurlong, CA. Make of that what you wish.

On the 140mm Tank Gun

Let’s talk some more about the 140 mm tank gun, that late cold war weapon that never was. Perfect for killing Soviet Supertanks that never were. And making your new tank way cooler than everyone else’s. The fastest way to get more armor penetration is to just build a bigger gun with more muzzle energy. A lot more.

As you might imagine, a 140 mm round is quite a bit bigger than a 120mm round. Let’s take a look, because these numbers are damned hard to find:

First, a typical 120 mm APFSDS round for the era, the American M829A1. The legendary Silver Bullet that slaughtered the tanks of Saddam’s Republican Guard. Some variations in length and weight are to be expected amongst 120 mm rounds. Newer rounds are a little heavier, but the size is constrained by ammunition storage racks and the existing chambers. The M829A1 is also the round that was in service while the 140 mm was under development.

M829A1 120 mm APFSDS
* Length: 984 mm
* Weight: 20.9 kg (46 lbs)

And now, the round to replace it. Producing 23 MJ at the muzzle, more than double that of the 120mm. The mighty 140. Dimensions were fixed by the NATO countries that were all developing their own versions of the round.

140mm tank round

XM962 140 mm APFSDS
* Length: 1,482 mm
* Weight: approximately 40 kg (88 lbs)

The length and weight of the 140 mm stand out. This round would have been a royal pain to handle. It’s also a bit fatter, so autoloaders could handle fewer rounds. This explains why the K2 Black Panther, otherwise similar to the Leclerc, can only hold 17 rounds in its autoloader compared to 22 in the Leclerc. The K2 is ready for 140 mm, needing only a barrel change. Interestingly, the round count in the Black Panther matches those for the M1-CATTB prototype, which had a similar, belt-style autoloader in its bustle. Don’t worry, we’ll talk about the CATTB in a future article.

NATO-standard 120 mm rounds like the M829A1 are unitary rounds. One big piece, like an oversized version of the cartridges you load into your guns at home. Because of the large size of the 140 mm rounds, these were made as two-piece rounds. Unfortunately, while I can find dimensions for the round’s overall length, I don’t have dimensions for the pieces. Until I can find one to measure myself, we’ll have to make do with some pixel counting/scaling, which yields a length of about 1,024 mm for the upper part of the round, and about 461 mm for the lower part. Which is still big and annoying for autoloader development. Length of the upper part of the round is heavily influenced by the length of the APFSDS projectile. This also would affect a design using a carousel autoloader like the TTB, since carousel (and therefore hull) height and turret height are constrained by the requirement to lift and rotate the rounds into position.

Based on the standards of the day, the 140 mm gun made more than twice the energy of the 120 mm at the muzzle. Of those 23 MJ of muzzle energy in the 140 mm, 14 MJ goes to the penetrator. Running the numbers meant that the 140 mm APFSDS could punch through more than 1,000 mm of RHAe at a ‘battle range’ of 2 km. For comparison, we’ll pull some open source estimates for M829A1, which give it a penetration of 700 mm of RHAe1.

Now, those are some really good numbers2. Of course, there’s a price to be paid. Even with the two-piece construction, everyone working with the 140 mm designed with autoloaders. Which meant significantly reworked turrets for the British, the Germans, and the Americans at a minimum. Plus, ammunition capacity would drop.

Upgunning to a 140 mm round was the simplest way to get a lot more armor penetration capability into a tank. At least from a weapon/projectile design standpoint. It would have required some serious reworking of then-extant designs, but such is life. When the Soviet Union imploded, the armored threat of the projected Future Soviet (super)tanks evaporated, and the 140 mm gun projects were quietly shelved. 120 mm rounds are continuing to get more development and the latest are quite a bit more effective than the M829A1. Lower cost, likely lower capabilities, but this decision makes sense given the circumstances.

  1. There’s some variation in this estimation depending on source. Open source disclaimers apply, etc. 
  2. They’re also a trifle disingenuous. Nobody is armoring their tanks with a meter of rolled homogenous steel. Literally nobody. A more advanced penetrator design can exploit effects on the not-steel that people actually armor their tanks with. Similarly, the armor might be designed to radically degrade (read: break up) the penetrator, which can be sort of but not really captured in RHAe estimations. So the RHAe numbers don’t actually tell the whole story on either side of the design puzzle. Oh, and the numbers themselves are the usual open-source estimates3, so they’re probably all wrong. 
  3. If you’d like to try your hand, start running through the Odermatt equation. And then remember that Odermatt wrote for tungsten-based penetrators, and M829A1 is depleted uranium, so you’ll need to tweak it. 


The M1 Tank Test Bed (TTB) was a late-80s prototype to test unmanned turret design concepts and compare them to a modern, manned-turret design: the then-state-of-the-art M1A1. The TTB was not necessarily intended to be what the next MBT would look like, but it was intended to shake out some design concepts and see if they were worth considering in the future. So let’s take a look.

m1 ttb

Some of you may notice a resemblance to the T-14. Both use similar unmanned turret design concepts. Such designs have been kicked around since the 1950s by many different groups of tank designers, and all for similar reasons of being able to reduce protected volume (and hence reduce design weight for a given standard of protection). The M1A1 weighs about 57 tonnes. The TTB, with a similar protective standard and the same 120mm gun (and a similar ammunition capacity) was reckoned to weigh about 15% less, for an approximate TTB weight of 48.45 tonnes. Interestingly, this is very close to the published weight for the T-14.

TTB also, of course, reduced crew to three men and put in an autoloader for ammunition handling. The design was intended to improve crew safety by completely isolating the crew from the ammunition. The autoloader itself was a large carousel, holding all ammunition below the turret ring. Let’s look at some pictures.

ttb autoloader

It’s sort of like the autoloader on the T-80, though NATO 120mm ammunition is one-piece, and is therefore a little more annoying to design an autoloader for. The autoloader built for the TTB held 44 rounds and this could be expanded to 48 or even 60 rounds with minor design changes. All of the ammo was stored in a ready configuration because the crew would be unable to move ammunition from a reserve magazine to the autoloader’s ready magazine (as on the Leclerc for example). The TTB autoloader was extensively tested, and could manage a rate of fire of one round every 12 seconds. Spent case bases or misfired rounds were ejected out a small hatch the back. The autoloader could be supplied through the rear hatch, and also had an unloading mode where it could slowly present rounds for removal. The autoloader weighed about 1,400 lbs. empty.

Some might question the vulnerability of such a design. However, statistically the vast majority of tank hits occur to the turret. Tanks like the T-72, for example, ran into trouble because of the ignition of their unprotected reserve ammunition stowage in the turret, not hits that set off ammunition in their autoloaders. And again, complete isolation from the ammunition should keep the crew relatively safe.

The TTB program was dialed back with the end of the cold war and was finally cancelled in the mid 90s. The autoloader design was used in the M1128 Mobile Gun System version of the Stryker.

As for the TTB prototype, it’s at the National Armor and Cavalry Museum at Fort Benning, and has recently been restored and repainted.

SOCOM, the USMC, and the Glock 19

The Glock 19 is Glock’s “Compact” pistol. It’s got a barrel length of just over four inches, has a height of about five inches, depending on sights, and holds 15 rounds in a magazine. It’s a great compromise between concealability and fightability, since it’s about as small as a pistol can be and still allow the vast majority of adults to get a full grip on the gun. The Glock 19 is a strong seller in the US civilian market, but it is also popular in SOCOM. They’ve even type-classed the Glock 19 Gen4 MOS. And the USMC has just ordered a large number of Glock 19Ms. And all this despite SIG winning the US Army’s Modular Handgun contract.

SOCOM has been the big user of Glock 19s for years in the DoD, so let’s look at them first. They’ve type-classed the Glock 19 Gen4 MOS with threaded barrel as the Mark 27. Type classing assigns a national stock number and makes it easy to order more in the future. SOCOM is a big user of the Glock 19, and this shows an eye towards the future of pistol sights: micro red dot optics. SOCOM’s current pistol red dot of choice is the Leupold Deltapoint Pro. While they could have selected a custom-milled solution, choosing the MOS model gives them something that can be ordered direct from the factory, and it allows them to easily switch optics in the future if desired.

The choice of Deltapoint Pro may be noteworthy, if only because it’s not the RMR that’s so commonly seen for duty-type applications. The RMR has significantly better battery life, and may be a bit tougher than the Deltapoint Pro. The Deltapoint Pro’s larger window makes it a bit easier for shooters to get used to, since there’s a larger area where they can see the dot. The biggest advantage of the Deltapoint Pro is that one can replace the battery without having to remove (and rezero) the optic. This more than makes up for the less than ideal battery life. Batteries can be easily swapped before missions or training sessions, without having to then verify the zero of the optic.

The Marines have opted for the same Glock 19M that the FBI adopted. Of course, the FBI also adopted the Glock 17M, and the reader may be wondering why not that pistol? Let’s consider the intended users. The Marines may espouse the concept of ‘Every Man a Rifleman’ but there are some jobs where this just doesn’t work. Pilots for example. A pistol also gives the option of carrying concealed, which is great for criminal investigators, and those conducting interviews. Or those that need to be around questionable allies. It allows the soldier to be armed without appearing to be armed. So the Marines are coming at it from the same way so many concealed carriers are: the Glock 19 is just about the perfect size. Smallness helps concealment, especially with respect to the “height” or “length” of the grip. And the Glock 19’s grip is about as small as it can be and still allow the user to get a full grip on it (i.e. no fingers are hanging off to be curled below it). The Glock 19 doesn’t give up much to the Glock 17 as far as shootability goes, but it’s quite a bit more concealable. For those who aren’t needing concealment, the pistol is still a secondary weapon system. A smaller, lighter pistol is easier to fit on their gear in a cockpit with all the other stuff they have to carry. Or on their belt for SOCOM.

The reader may also be wondering “Why not the P320 Compact?” Well, the Marines do have a history of working a lot with both SOCOM and the FBI, and they both like Glocks. Also, the MHS program was not as thorough as the FBI’s tests were as far as high round count reliability tests are concerned. The full-size MHS entrants (P320) went through 12,500 rounds to check reliability and establish an MRBS of 2,000 rounds with a 90% confidence level. The compact entrants (P320C) only had to go through 1,500 rounds of evaluation. The FBI tests included 20,000 rounds for each of the full size and compact entrants. So the Glock 19M has verified reliability in a way that the P320C doesn’t.