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Author Archives: parvusimperator
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:
| XM307 | M2 | Mk. 19 | |
|---|---|---|---|
| length | 52.2″ | 65.1″ | 43.1″ |
| barrel length | 25.1″ | 45.0″ | 16.25″ |
| weight | 50 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
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.
Huh.
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.
USASOC’s URG-I for the M4
Thanks to SHOT Show and the good folks at Brownells, we can see what the US Army’s Special Operations Command is doing to improve their M4s. Let’s take a look. First, the product page.
Now, there are a bunch of things to note here. The upper receiver is unchanged. Still has that forward assist and that dust cover. The 14.5″ barrel is made by Daniel Defense, who have some excellent cold hammer forges for such things. The barrel has some unspecified improvements to work better with M855A1 ammunition, which has an exposed, hardened steel tip. I would expect these changes to be to the geometry of the feed ramp in the barrel extension, but I can’t confirm this yet. And I don’t know if there are other changes. The rest of the barrel is pretty boring. 1:7 twist rate, that government profile,1 and a midlength gas system. The midlength gas system is a noticeable difference, being somewhat longer than the standard carbine length. A midlength gas system is somewhat softer recoiling, and probably leads to improved reliability when using a suppressor (which increases the gas pressure in the system). Note that they did not specify the medium-weight “Socom” profile barrel. Overkill for expected uses? Not proven? Weight Conscious? I’m honestly not sure.
The handguard is Geissele’s Mk 16, and is 13″ long and free floated. It has a picatinny rail at the top and Mlok slots all around2. This is a big improvement over the usual plastic handguard or the KAC RAS system, which has picatinny rails and isn’t free floated. Plus a longer rail means more room for one’s hand as well as accessories. The older handguards had room for lights and lasers or your hand, but not both. Geissele handguards are very nice, and have a well-designed attachment system.
The full length handguard means the standard triangular front sight block has to go. It’s been replaced by the Geissele Super Gas Block, which is low profile, and held in place by two setscrews and a taper pin. I like pinned gasblocks. They’re sturdier. Good choice here.
Geissele also makes the charging handle. It’s bigger, sturdier, and better suited to just grabbing or pulling at one side, like lots of modern guys do. It’s a fine choice.
The other difference in play is the muzzle device. The Brownells version (for civvies) has the Surefire S3F, which is a three-pronged flash hider that also serves as an adapter for the quick-detach mechanism used in Surefire’s silencers. The military is probably getting the S4F (with four prongs). I don’t know why the difference there. It’s still a suppressor adapter, and remember, Surefire’s silencers won the SOCOM testing.
Overall, I’d say it’s a pretty solid set of improvements, and results in a gun better than the previous PIP proposal. I would like to see more if it were up to me, namely a better barrel profile and some bolt carrier group improvements. Both Lewis Machine and Tool and Knights Armament have some available improvements there, and I’d like to see some evaluations. Especially if suppressors are going to be used a lot.
Will I buy one? No. I don’t have much use for factory uppers these days. Building my own isn’t hard, and then I get to make all of the parts choices, and get things suited for me and my uses. And I don’t do clone builds. But it’s a solid upper if you’re in the market for one.
Finally, let’s do a quick weight comparison with the upper for a standard M4. The lower is separate, and needs no changing provided it has the safe/semi-/full-auto trigger group. Some of these weights are approximate because of what is and isn’t available on the market yet, but I wouldn’t expect them to change too much. I’ll update these as I get better numbers.
| Part | M4 | Weight (lbs) | URG-I | Weight (lbs) |
|---|---|---|---|---|
| Barrel | 14.5″ gov’t. carbine gas | 1.6 | 14.5 gov’t. mid gas | 1.5 |
| Upper receiver | A3 | 0.6 | A3 | 0.6 |
| Handguard | double shield | 0.72 | Geissele Mk 16 (13″) | 0.92 |
| Gas Block | FSB | 0.33 | Geissele sgb | 0.1 |
| Gas Tube | carbine | 0.04 | midlength | 0.05 |
| BCG | standard | 0.72 | standard | 0.72 |
| Muzzle Device | A2 Birdcage | 0.14 | SF4P | 0.28 |
| Charging Handle | standard | 0.08 | geissele sch | 0.09 |
| TOTAL | M4 | 4.23 | URG-I | 4.26 |
Notes: Upper receiver weight includes the dust cover and forward assist. Listed handguard weights include all mounting hardware. The Mk. 14 only has Mlok slots at 3:00, 6:00, and 9:00.
Not bad. Despite the stupid government profile barrel, only a little weight was gained. At least according to my back of the envelope calculations, and that’s a win More capability without a lot more weight.
Edited 09/12/18 to use correct weights for the Daniel Defense 14.5″ CHF Government profile midlength gas barrel, Geissele Mk 16 handguard, and Surefire SF4P flash hider.
- Which I hate. A lot. It’s profoundly stupid, but that’s probably why it’s called the “government” profile. I guess we can’t expect them to fix everything at once. ↩
- “All around” being 1:30, 3:00, 4:30, 6:00, 7:30, 9:00, and 10:30. Also, Mlok is lighter than picatinny rails, woo. And some study found it tougher than the rival keymod. ↩
Parvusimperator Reviews the PX4C
Okay, this is Fishbreath’s gun, it’s true. And I’ve been pestering him to review it, but he hasn’t.
Fine. I’ll review it.
Don’t worry, Fishbreath. I’ll do my best to be impartial.
The PX4C (Compact) is a newish double action pistol from Beretta. Well, certainly newer than the Beretta 92, which is what you probably think of when I say “Beretta handgun”. The PX4C doesn’t have a ton of market share, partially because Beretta is bad at marketing, partially because Beretta hasn’t kept market share amongst law enforcement departments (see: Is Bad At Marketing), and partially because the PX4s came out a bit too late. The PX4s were released in 2004, when double-action triggers were going out of vogue. And there they have more or less stayed. If they came out in the 90s, back when double action triggers were Still Cool, they would have sold like crack, and you would hear lots about how nice they were.
Which brings us to an obvious point. These are double action semiautomatics. I am not a fan of these, personally. If you are not either for whatever reason, then (1) these will probably not make a convert out of you and (2) these can’t be turned into something that they aren’t: a striker-fired or single action only pistol. If you want something else, get something else.
On the other hand, if you are a fan of double action pistols, then the PX4C is a great choice, because it is about Glock 19 sized and polymer framed. The Glock 19 size (roughly) is big enough that you can easily get a good grip on the gun, but small enough that most people won’t have too much trouble concealing it with a modicum of effort. You can get good shooting smaller pistols, and you can conceal bigger pistols with a little more effort, but the Glock 19 is the sweet spot of balancing concealability and firepower. This gives you the same size package, the same fifteen round capacity, but a double action trigger. It’s also the only game in town if you like the double action trigger and want something in the Glock 19 form factor (and don’t feel like giving up a couple rounds). That’s really cool.
Oh, and polymer framed because it’s nicer to carry less weight around on your belt.
The PX4C has the Beretta-standard safety/decocker on the slide. I’m not a fan of this location, but it’s easier to reach with your strong hand than on a Beretta 92. You can convert it to a decocker-only lever with a really easy parts swap, and these parts are easy to come by.
I’ve also heard some occasional stories of issues if these pistols get dry, like in high round count classes. To the best of my knowledge, this hasn’t happened to Fishbreath, but he doesn’t do 2,000 round marathons of shooting. The PX4C might be a little needier of lubrication than, say, a Glock. I don’t know enough about this to know how big an issue it is. The occasional story comes up. I can’t confirm the cause either. The rotating barrel system is different, for better and for worse. It does make the pistol a bit softer shooting, but 9 mm isn’t all that stout to begin with. It might be more interesting to try one in .40, but I don’t have access to one.
The PX4C comes with interchangeable backstraps, which is nice. They could be grippier, but I say that about everything. This is easy to fix with some stippling or skateboard tape. Or maybe you like a smoother grip, in which case the PX4C is perfect for you as-is.
There’s actually a decent amount of Beretta parts support for these. There are low-profile safety/decocker levers, low profile slide releases, and a variety of sizes of mag catches. You can also use the mainspring from a Beretta 8000D to improve the double-action trigger pull by a significant amount. And, unfortunately, there is where the support stops. With searching you can find holsters. It is very difficult to find sight alternatives, though Trijicon does make both their standard three-dot tritium sights and their HDs for the PX4s. Stock sights are three-dot units.
So there you have it, readers. The PX4C is a great option for you if you like to carry reasonably-sized double action pistols. In which case, you owe it to yourself to give these a go. They’re pretty easy to overlook given all of the fancy Beretta 92 variants of late, but these are quite a bit easier to carry.
Also, if you’re on the fence, there’s an Ernest Langdon Custom Carry Edition, with actually good sights and all of the low profile controls added right out of the box. It also even comes with some grip tape. This is the version I would suggest you get, dear reader.
On Glock Safeties
A few weeks ago, Fishbreath and I were looking at another striker-fired pistol1 being found to be not drop safe. Fishbreath commented that he’d really like to see these barrel-up-at-30-degrees drop tests done to the Glock 43 and the M&P Shield. I promptly obliged him with a video. Glocks have three safeties designed to work together to prevent firing when dropped at any angle. Let’s take a look at how they work. An understanding of the trigger mechanism and the safeties it employs is also useful when attempting to modify that trigger system.
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SIG P365
The market for small single stack (and staggered-single stack) pistols for concealed carry is huge. In my eyes, they’ve neatly usurped the old S&W J-Frame in the small concealment weapon space. Perfect for NPEs and the backup gun role. For my money, I’d much prefer striker fired triggers to heavy double action revolver triggers. Plus, the sights on the Glock 43 and M&P Shield are easily interchanged. Sights on most J-Frames aren’t. And what comes on the gun are atrocious.
So it makes sense that SIG would try to get in on this market. Using the same sort of striker-fired action as in their P320, they’ve come out with the P365. It’s sized in between the Glock 43 and the M&P Shield, as seen below
From left to right: Glock 43, P365, M&P Shield.
What makes the P365 special is the capacity. Where the Glock 43 holds six rounds with the standard, nonextended basepad, and the Shield holds seven rounds with the standard, nonextended basepad, the P365 holds ten rounds with the standard, nonextended basepad. It’s still thin and small, so it will still conceal very well. But more bullets. More bullets is better. Otherwise, ergos are very much a slimmed down P320. I’d expect the trigger to be like the P320 as well, so short and heavy and doing its best to resemble the single action trigger of something like a P226 or P229. Eminently shootable to be sure, and way better than the trigger on a J-Frame.
This idea sounds like a winner. And it probably will be. I have my reservations, at least as of when this goes to press. First, I don’t like to buy first generation anything for firearms. I am not a beta tester. I am not a member of anyone’s QC department. And I don’t do that work for free. So I’ll wait a little, just to make sure the bugs are gone. And that goes double for anything that says SIG on the side. Between the P320 drop-safety recall and their history of QC problems with their traditional P22X guns since setting up the plant in Exeter, they get an even longer wait. I do not like the current management either.
All that said, I would like this gun to work well, because I’d love a small backup gun with more bullets.
On the Glock 19X
Glock has released their MHS entrant to the civilian market: the Glock 19X.
It’s got all the Gen 5 improvements: no finger grooves, an improved trigger, and ambidextrous slide stop, plus the texture and replaceable backstraps from the Gen 4 models. By all accounts, the Gen 5 models are awesome. I’m most excited about the improved trigger. It’s better than previous factory models and very competitive with the aftermarket options.
Of course, there are Gen 5 options available for the Glock 19, the Glock 17, Glock 34 MOS, and Glock 26 out there already. The Glock 19X is different. It pairs the full-size frame of a Glock 17 with the compact slide and barrel of a Glock 19.
Glock made this design to fit the “box” of the MHS size specifications. It will probably do well on the civilian market, as short-slide, full-size grip 1911s, snubnosed K-Frames, and subcompact pistols with grip-extending magazines are very popular.
I’m not a fan of the 19X from a concealment perspective, because the height is more annoying to conceal than the length. If I’m going to carry a full-size grip, I might as well get the sight radius of a full-size gun. Plus, those tend to recoil a little softer. I’d be a little more interested in a Glock 19 frame with a Glock 17 slide and barrel for concealment, but that’s just me.
However, if you wanted to build an Open Glock, the Glock 19X is a great base gun. It just needs an MOS model or some milling for an optic. The shorter slide means that if you opt for a smaller compensator like the KKM or Black Rifle units, your pistol will fit in a Glock 34 holster. So you’ll be able to find a holster quickly and cheaply. With a bigger compensator like the SJC, you’ll still have a shorter overall pistol to help transitions, plus a lighter slide that improves recoil characteristics.
You also get the longer, Glock 17 grip. This is nice partially because I prefer the grip on the Glock 17. Your mileage may vary. What doesn’t vary are the magwell options. There are a wide variety of large, competition magwells available for the Glock 17 size frame. Small differences make these not viable for Glock 19s. Bigger magwells are more forgiving than small ones. Plus, there are a wide variety of materials (and therefore weights) available.
There you have it. A concept with plenty of admirers, albeit for different reasons. It’s good to see more options.