The Reloading Press is an at-least-weekly feature here on Gaming Ballistic for 2016. Each week it looks at some interesting real-world cartridges and presents them with hopefully-useful information in GURPS Format.

.50 BMG (12.7x99mm)

The .50 BMG is an iconic cartridge. It virtually defines “large bore rifle” in the modern world – or at least the Western world –  which isn’t bad for a cartridge designed in 1918 or so based on a scaled-up .30-06.

It’s available in a bewildering array of chamberings, and is one of the standard military-grade projectiles that’s actually useful and feasible to start to do cool things with, like have saboted or explosive projectiles.

This cartridge has been fired out of everything from pistols to rifles to machineguns to gatling guns, from the ground, sea, and air. If there’s been a fight in the last 100 years that involves a military force, odds are someone cracked one of these off somewhere.
Ballistic’s Calculator Inputs

Basic inputs for the calculator are as follows, selecting 1100mm for the barrel length, which is basically the barrel length of the standard M2HB machinegun.

INPUT
.50 BMG
Chamber
Pressure
55000 psi
Barrel
bore
12.7 mm
Case
Length
99 mm
Chamber
Bore
19.2 mm
Barrel
length
1100 mm
Bullet
Mass
647 grains
Aspect
Ratio
3.8 L/Bore
Burn
length
25.01508442 mm
Projectile
Caliber
12.7 mm
Total
Accelerated Mass
647 grains
Expansion
Ratio
1 expansion
Output Stats

The entire platform was designed around the 810mm barrel of the M99 single-shot platform.

Notes

  • The velocity is at the muzzle. The velocity with a 1100mm (about 45″) test barrel is tuned to match real-world data at 3,150fps with a 395gr turned-brass bullet. 
  • With damage as high as it is, I didn’t do the point-by-point barrel lengths, in most places, but at the pistol level and the barrel lengths that usually distinguish portable rifles (18-28″), I broke it down a bit.
  • An unusual word about DnD damage – the nice thing here is that from 24″ to 45″, the damage is the same, at about 2d12, which is the value listed in d20 Modern (3.5edition based).
Well, of course someone went and made a pistol out of something originally designed to fire out of a barrel nearly four feet long using a linked feed, so the chart goes all the way down to about a foot worth of barrel. Which is, it might be noted, only 3x the length of the cartridge.

By and large, once you get out of crazy-land, this projectile (which should match the original M2 ball round, at 647gr and 920m/s out of a 45″ machinegun barrel) does either 6dx2 or 7dx2 for penetration, and will still deliver 6d pi+ or 7dpi+ a kilometer away. Max range is on the order of 6km (my calculator shows 6,300yds). (Note that the pi+ is by GURPS rules-as-written, where size modifiers are strictly based on caliber. My sheet uses a momentum-based formula, and so the huge bullet of the .50BMG takes the projectile over the top to a 2.1 Wound Channel Modifier. It’s still a crap-ton of injury in either case)

Alternate Loads

There are a lot of different loads here. The most energetic solid projectile on Wiki is an 800gr bullet at about 2,900fps, which will do 15d instead of 14d from an 1.1m barrel . . . but which 1/2D range increases to something like 1,250yds, with a max that extends to 7,770yds, largely due to the aspect ratio of the projectile.

Armor piercing versions of the basic round exist, which use a hardened steel core instead of a mild steel one. Based on the limited information I could find, this is roughly a 20-25% boost in penetration over the basic ball round, which is more like +1 per die than the usual (2). 

A projectile so egregiously overpowered that every gamer will want more, the M903 (and its tracer cousin) fire 360-gr tungsten projectiles of roughly .30 caliber and 5:1 aspect ratio out of a saboted projectile. These things leave the barrel at about 4,000fps, and will penetrate over DR 90 at 500m. Earning its (2) armor divisor, that suggests about 45 points of penetration at 500m, or about 12d+2. My calculator gives about 16d at the muzzle, and . . . 45.3 points of damage at 550yds/500m. So booyah, and this is why I use this thing.

Finally, the “I’ll have my cake and eat it too” projectile, the Mk211 Mod 0 fires a 671gr projectile at 886m/s for 14d-1 damage, but it also packs a tungsten core and 13 grains of Composition A explosive and another 13 grains of incendiary compound. That’s less than a gram of each, and almost certainly is to enhance fragmentation effects. Clearly the designers of this projectile did not get their coffee that morning, cause they were feeling nasty. With so little explosive, I’d just treat it as a x3 modifier against living critters due to internal explosions, and also give it the ability to set fires for flammable objects.

This web page at survivalmonkey.com represents the best consolidation of information I’ve ever found on the .50BMG.

Platforms


SHTF Safety Harbor Firearms

The .50 BMG is a very popular cartridge, especially in the hands of military operators that don’t have to tap-dance to justify owning one. However, the price of entry for such a beast is quite steep, and the lowest I could find for a single-shot, bolt-action rifle clocked in at $2,000 . . . and that’s just the rifle. If you want to shoot at a mile or two, you’ll need a high-quality optic that will probably run you just about as much – a popular model seems to be Schmidt and Bender, and one of those can run you $2,500-3,000.

And there are always ways to pay more. That being said, with the right ammo and the right scope and the right shooter, you can deliver a 2.6″ 5-shot group at 1,000 yds (that was the world-record at the time), which in GURPS is about Acc  7.5.

So, some rifles, then:

The Safety Harbor Firearms company can get you into a .50BMG for the lowest price out there that I could find, at under $2,000 for a single-shot bolt-action rifle with a 29″ barrel. Spend a tetch more and you can feed from a 5-round box.

Armalite AR-50 is on the “low” end of price for single-shot, bolt action rifles. It clocks in at 34 lbs (!), is nearly five feet long, with a 30″ barrel.

Bushmaster’s BA50 is a bolt-action rifle with a 10-round box magazine. It runs $5,600 and weighs 30 lbs as well. It disassembles like an AR15, so familiarity is there for many shooters.

Desert Tech makes a pretty sweet bullpup style rifle for the low-low price of around $7,600, which only weighs 20 lbs, sports a 5-round box magazine and a 29″ barrel. They have a cool on-line configurator as well, which is a good way to waste some time.

If you’ve got $12,000 to spare, check out the McMillan TAC 50 A1-R2. 26 lbs, 29″ barrel, and bolt action with a 5-round magazine.

And finally, you can’t talk about .50BMG without talking about Barrett Firearms. They basically have come to define the genre in many minds, and certainly the minds of Hollywood, where nothing quite says .50BMG like a Barrett, and they were even modded up to be railguns in a forgettable Arnie flick.

They come in bolt action (M99), bolt-action bullpup (M95), and conventional layout semi-automatic (M82 and M107). There was an XM500 semi-auto bullpup at least in development for a bit, but not sure what happened to that one.

The Reloading Press is an at-least-weekly feature here on Gaming Ballistic for 2016. Each week it looks at some interesting real-world cartridges and presents them with hopefully-useful information in GURPS Format.

.600 Nitro Express (15.7x76mm)

The .600NE is an “elephant gun” cartridge introduced in 1903, and was the largest round used in the “heyday” of African safari big-game hunting. It’s a gigantic round (only outsized by the .700NE in this lineup) requiring very large and heavy weapons (13-20 lbs) to carry.

It’s large, very powerful, and not well engineered relative to more modern weapons (no one should expect otherwise – it was a 1903 answer to a 1903 question, and more modern bottleneck rounds can penetrate more, be more accurate at range, and be fired from a more robust, modern combat platform.

But very few will be quite as pretty. The rifles that shoot such a beast (such as the H&H Royal) are spectacular instances of a gunsmith’s art.


Ballistic’s Calculator Inputs

Basic inputs for the calculator are as follows, selecting 559mm for the barrel length. That’s on the shorter end of the usual range for such a rifle as produced by H&H; so few of these guns exist that it’s hard to get a truly “representative” value for such a bespoke weapon.

INPUT
.600 Nitro Express
Chamber
Pressure
40000 psi
Barrel
bore
15.7 mm
Case
Length
76 mm
Chamber
Bore
15.7 mm
Barrel
length
559 mm
Bullet
Mass
900 grains
Aspect
Ratio
2.5 L/Bore
Burn
length
39.7 mm
Projectile
Caliber
15.7 mm
Total
Accelerated Mass
900 grains
Expansion
Ratio
2 expansion
Projectile
Load
1
Output Stats

The output from a notional double-rifle with 22″ barrel.

Notes

  • The velocity is at the muzzle. The velocity from a 22″ barrel was tuned to 2000fps with a 900-gr solid bullet. 
  • With damage as high as it is, I didn’t do the point-by-point barrel lengths, since the difference between 10d and 10d-1 is in the “who cares” range for most lengths, but since one of the questions that has come up is which does more damage, the .600NE or the .700NE, I did do fine-grades around 10d

Alternate Loads

These monsters are mostly hand-built anyway, and can cost $50-300 per round. Of course, with what the platforms cost ($20,000 isn’t crazy talk, nor is $120,000), and trips to Africa for safari (which is where such weapons are mostly used) being $10,000 more, spending a grand or two for ammunition isn’t going to break anyone.

But by and large, you fire gigantic solid projectiles out of these guns, witness the .700NE compared to a .45ACP to the right.

Platforms

There are basically two platforms that you will use to launch this monster. A ridiculously well-made custom rifle that will likely cost you thousands, tens of thousands, or even hundreds of thousands of dollars, and weigh 13-18 lbs to boot, or a custom cut-down pistol that even Hellboy would cock an eyebrow at, though it would be an approving one, I suspect.

The classic .600NE is a double-rifle, basically two rifle barrels side by side, designed to give a rapid follow-up shot against a charging cape buffalo, bull elephant, or armored division.

These rifles are often heavily decorated, worked in gold or silver, and use only the finest woods for furnishings. It is not unusual to see the big-bore offerings go for $100,000 or even more for a used one.

For pistols, it’s really a matter of an exercise in gun design and “you can do it, but why would you?” than any real practical methodology. The weapons (two featured prominently in internet pix) are gigantic, require two hands to hold, much less to shoot, and the recoil would be spectacular. 

As you can see, these firearms are more of an engineering exercise when compressed to pistol size than anything else. While I’m sure there are RPG characters somewhere who would want to carry one, a short-barreled rifle format would be not much larger and at least give three points to brace (and injure yourself) instead of two.

Nonetheless, it can (and has) been done, and has been, with the T/C style pistol having a 14″ barrel and thus hitting for about 9d damage.

Comparison: .700NE


I’m not going to work this one up in detail. Suffice it to say that the 1000gr projectile at 2000fps is quite a bit larger in bore (though shorter; it’s a puny thing from an aspect ratio perspective), which mitigates to a large degree the increase in energy from the larger mass. It’s within a point of damage (a tetch higher) of it’s smaller .600NE cousin.

GURPS formally gives both cartridges 5dx2 pi++ damage. GURPS gets it right.

The Reloading Press is an at-least-weekly feature here on Gaming Ballistic for 2016. Each week it looks at some interesting real-world cartridges and presents them with hopefully-useful information in GURPS Format.

.380 ACP (9x17mm)

The .380 ACP was another design by legend John Browning, and this one was to create a pistol that could use the blowback action, which allowed the barrel to be fixed in the frame and thus more accurate. More powerful rounds required the tilt-barrel action.

The chambering first appeared in the Colt Model 1908, and has been a fairly popular self-defense pistol ever since. More modern thoughts about the smallest caliber for self-defense being 9x19mm were definitely not in force back then, and several militaries adopted the .380ACP for handguns (as well as the even-smaller .32 caliber) prior to WW2.

After that, it was pretty much the .45ACP or the 9x19mm Luger.

There’s no deying it, though – firearms made with this cartridge can be ridiculously tiny, and it’s far easier and more effective to defend yourself with the tiny pistol in a coat or pants pocket than with the larger, more effective one you had to leave behind in your home or vehicle because it was too large to comfortably carry.

The .380 ACP, like the even-smaller .22LR, can injure and kill folks, and has been used to do exactly that for over 100 years.

Ballistic’s Calculator Inputs

Basic inputs for the calculator are as follows, selecting 95mm for the (test) barrel length.

INPUT
.380 ACP
Chamber Pressure 21500 psi
Barrel bore 9 mm
Case Length 17 mm
Chamber Bore 9 mm
Barrel length 95 mm
Bullet Mass 95 grains
Aspect Ratio 1.4 L/Bore
Burn length 5.14 mm
Projectile Caliber 9 mm
Total Accelerated Mass 65 grains
Expansion Ratio 1.6 expansion
Projectile Load 1
Output Stats

The .380 APC is pretty much good for one thing, though it does that well – it’s one of the most powerful (“powerful”) rounds that you can put inside a blowback pistol action, or at least, it was that way for perhaps 100 years or so. 

Notes

  • The velocity is at the muzzle. The velocity with a 95mm test barrel is tuned to match real-world data at 270J with a 95gr FMG bullet. This is not the highest energy available, but if you’re looking for energy dump, you’re looking in the wrong place.
  • If you’re going to carry a 5″ barrel, carry something powerful. But in the 2.5″-5″ range, you’re looking at 2d pi damage, and so there really isn’t going to be a lot of variation in the stats here. Even the most powerful rounds in wiki will only do 2d+1 at 300-330J. 
  • The heaviest bullet that can be safely loaded in the .380ACP is 115gr. 85-95 gr is the usual.
I suspect that the core of the distribution – 2d with barrels from 2.5-5″, is more or less the end of the road here.

Alternate Loads

The only important alternate is going to be a JHP round for enhanced wounding. The official damage there would be 2d (0.5) pi+, which is only going to be friendly on unarmored targets. The ballistics program I use will tell you 2d-1 pi+, which is much more friendly, and explains why the round still has some adherents today in its niche of “capable of being carried in a tiny pistol.”

Platforms

There are many small-frame handguns chambered in .380ACP. The first that deserves mention is, of course, James Bond’s weapon, the Walther PPK. That was not the first .380 ACP, but it’s probably the most iconic.

Other pistols include the “slimline” Glock 45, the Kahr P380, and the tiny, tiny Seecamp LWS-380, which can disappear into a palm.

The not-small category also includes the (in)famous MAC-11, which could empty a 32-round magazine in 1.6 seconds of continuous fire, likely resulting in severe damage to the buildings behind your target and the very dangerous air around and above the intended victim.

Wiki has a nice rundown of other .380ACP firearms.

The Reloading Press is an at-least-weekly feature here on Gaming Ballistic for 2016. Each week it looks at some interesting real-world cartridges and presents them with hopefully-useful information in GURPS Format.

.416 Barrett (10.6x83mm)

I was laboring under the impression that the .416 was just a .50BMG necked down to .416. This proved to be incorrect – at least to a certain extent.

The design philosophy was more or less to unapologetically design a purpose-built long-range sniper cartridge for work at the very long engagement distances that US troops were encountering. The bullet itself was targeted for weight (about 400 grains) and turned down from solid brass on CNC machines. While this is more expensive, it makes for a very high ballistic coefficient (0.74) and the manufacturer claims that it stays supersonic well past 1500 yards (I believe it).

The entire purpose of this one was to deliver a supersonic projectile at over a mile, to enable very accurate shot placement. That’s a bit beyond the scope of the ballistics calculator . . . but this projectile is a monster. It’s a projectile that masses 6x what the current M855 does, but travels every bit as fast. As you’d imagine, it makes quite an impression
Ballistic’s Calculator Inputs

Basic inputs for the calculator are as follows, selecting 810mm for the barrel length.

INPUT
.416 Barrett
Chamber
Pressure
57000 psi
Barrel
bore
10.6 mm
Case
Length
83 mm
Chamber
Bore
18.6 mm
Barrel
length
810 mm
Bullet
Mass
398 grains
Aspect
Ratio
4.62 L/Bore
Burn
length
26.86 mm
Projectile
Caliber
10.6 mm
Total
Accelerated Mass
398 grains
Expansion
Ratio
1 expansion
Projectile
Load
1

Output Stats

The entire platform was designed around the 810mm barrel of the M99 single-shot platform.

Notes

  • The velocity is at the muzzle. The velocity with a 810mm (almost 32″) test barrel is tuned to match real-world data at 3,150fps with a 395gr turned-brass bullet. 
  • With damage as high as it is, I didn’t do the point-by-point barrel lengths, since the difference between 12d and 12d-1 is in the “who cares” range.
There are not too many barrel lengths out there. There’s the standard 810mm barrel, and a few others from different rifles.

They’re all long, though. While this projectile/cartridge combination would benefit from a bullpup configured rifle, the test barrel coming in at about 32″ means this thing is a beast no matter what. And past the 740mm to 840mm range where 12d-ish happens, you’re really not helping yourself much (two extra points of damage? Why bother?).

Alternate Loads

While there may be alternate bullets, and I did read that cheaper jacketed lead bullets were “forthcoming,” as far as I could find, there’s but one projectile here – the turned-down brass solid bullet. 

Platforms

Barrett M82A1



The basic platform that is the test platform is the single shot M99, which will run you about $4,000.

Barrett M99 Single-shot

The M82A1 gives you a box magazine likely of 10 rounds, and is nearly $9,000 . . . and that’s without an optic, on which you’ll want to drop a whole lot of money, because why get a rifle that can reach out over a mile if you can’t see the target?

McMillan TAC-416

Finally, if you don’t want Barrett, you can go McMillan or Armalite. The Armalite is a $2,500-$3,000 rifle (again, no optic). The TAC-416 is hard to find and harder to find pricing for, but the 50-cal version seems to run around $10,000. Yow.

These are special platforms for special applications, and amateurs need not apply. Or they shouldn’t. But for the truly needful, and truly rich, you can nab a system that has validated 0.4 Minutes of Angle capability. The math puts Acc 7 for a GURPS rifle at about 0.36 MoA so basically, drop $10K on a rifle, another $4K for a Schmidt and Bender scope, and then any other customization you want, plus the ammunition (which after that is the least of your worries).

The Reloading Press is an at-least-weekly feature here on Gaming Ballistic for 2016. Each week it looks at some interesting real-world cartridges and presents them with hopefully-useful information in GURPS Format.

.224 BOZ (5.56x25mm)



The .224 BOZ is a wildcat cartridge developed in the late 1990s. It is basically an attempt to defeat body armor out of a pistol-sized cartridge, and to all appearances, the attempt was successful. It comes in two versions, the original parent case, which is based on the 10mm Automatic (10x25mm Auto), and another in 9mm, which explains the size differential in the two cartridges featured in the reference image to the right.

This installment of the Reloading Press is more about design philosophy and getting the most out of a cartridge than a real-world example of something that was or will be deployed.

With that, we’ll look at two ways of using a 10mm cartridge case to launch a pretty neat projectile – the 69-grain “super penetrator” from this PDF file. While I’m sure there’s plenty of marketing hype there, you can’t get too much more “designed as armor piercing” than a long projectile with a tungsten carbide lead penetrator mated on top of a hardened steel core beneath it.

There are two ways to launch this one. The .224 BOZ way, and the APDS (Armor Piercing Discarding Sabot) way. Sabot ammunition is very commonly used in KE penetrators for tank guns, and less commonly used in small arms. The .50BMG has a SLAP (saboted light armor piercing) version, and there are nifty “accelerator” rounds that, for example, launch a .223 bullet out of a .308 barrel at 4000+fps, with a mechanism pictured on the right – a plastic sabot cup that fits in the full-caliber cartridge. The APDS pathway is fully supported in GURPS High-Tech.
Ballistic’s Calculator Inputs

Basic inputs for the calculator are as follows, selecting 117mm for the (test) barrel length. The version presented here is the .224 BOZ, with a 5.7mm 69 grain projectile. The same projectile will be used in both cases.

INPUT
.224 BOZ from 10mm Auto case
Chamber
Pressure
37500 psi
Barrel
bore
5.7 mm
Case
Length
25 mm
Chamber
Bore
10 mm
Barrel
length
117 mm
Bullet
Mass
69 grains
Aspect
Ratio
4.75 L/Bore
Burn
length
11.6 mm
Projectile
Caliber
5.7 mm
Total
Accelerated Mass
69 grains
Expansion
Ratio
1 expansion
Projectile
Load
1
Output Stats

The cartridge develops a healthy velocity of 1442fps (440m/s) out of a 117mm barrel. Fine, but not that impressive necessarily, considering you can fling a much heavier bullet (180gr) at 400m/s out of a 400mm barrel with the bog-standard 10mm.

A standout feature of the projectile itself is the outstanding 1/2D range, due to the sectional density.

Notes
  • The velocity is at the muzzle. There is no “tuned” or “test” velocity, but at least by the reckoning of the program, the observed behavior of the .224 BOZ, which is 2500fps with a 50-gr bullet, is not realized until over a 19″ barrel. At that point, carry a full-sized .223
  • Out of a roughly 9″ barrel, you’re looking at 3d+1(2) pi-. That’s pretty good penetration, actually, but the wound channel requires vitals hits. The heavy recoil of the 10mmAuto might be tamed by the lighter bullet, but maybe not.
Now let’s flip over to launching the same projectile out of a full-caliber barrel, from the same cartridge case. That requires only changing the barrel bore to 10mm, and the total accelerated mass to about 15% higher than the launched mass – sabots for .223 from a .30 case only weigh 6 grains, so allowing more for the larger pistol case makes some sense. We’ll assume an 79.5gr total mass.

What happens? Well, here are the inputs:

INPUT
10mm APDS
Chamber
Pressure
37500 psi
Barrel
bore
10 mm
Case
Length
25 mm
Chamber
Bore
10 mm
Barrel
length
487.8932844 mm
Bullet
Mass
69 grains
Aspect
Ratio
4.75 L/Bore
Burn
length
11.6 mm
Projectile
Caliber
5.7 mm
Total
Accelerated Mass
79.5 grains
Expansion
Ratio
1 expansion
Projectile
Load
1

And let’s look at the barrel lengths required to get the same range of performance. Actually, we can’t, because even out of a snubnose barrel, the APDS round simply is better than the full-bore barrel. Why? Force. The pressure is held constant, and the 10mm sabot allows for 3x the force to be applied to the projectile over the same distance.

Now, there are a ton of assumptions in the model, the first being the the same cartridge case and the same powder load, or at least same pressure profile, will result in the same psi on the back of the bullet. But given those assumptions, developing a saboted PDW cartridge would seem to be a much, much better design direction than the full-bore 4.6 and 5.7mm projectiles fielded today.

In GURPS, certainly this is true. As it turns out, the rule of thumb for APDS is 1.3x damage and add a (2) armor divisor. For a 10mm pistols, you’re probably looking at 3d-1 or 3d damage by the official rules, that would gross up to about 12.3 to 13.6 points, or 4d-1 (2) pi-.

Note that out of a 115-125mm barrel (pistol-sized), my calculations give . . . 4d-1 (2) pi-.

So if you’re looking for good damage out of short barrels, you might be paying $100 for 50 rounds . . . but you can basically outperform nearly all of the PDWs on the market today with both pistols and SMGs. 

The Reloading Press is an at-least-weekly feature here on Gaming Ballistic for 2016. Each week it looks at some interesting real-world cartridges and presents them with hopefully-useful information in GURPS Format.

10mm Auto (10x25mm)



The 10mm was designed by none other than Colonel Jeff Cooper. Created to be a flatter shooting cartridge than the .45 ACP but hit harder and wound better than the 9mm. When you take a projectile that is substantially heavier than the 9mm, larger diameter, and have the audacity to throw it 100fps faster as well, success is a foregone conclusion.

At least by that metric. Undoubtedly a powerful cartridge – the heavier loads outthwack a .357M – it earns its power by being large, kicking hard, and being generally hard to control. The same problems that exist with large autos in .44M or even the mighty .50AE but on a smaller scale.

The cartridge’s power drew the attention of the FBI in the wake of the famous Miami shootout, and the cartridge was selected as the standard FBI chambering in the S&W 1076 in 1989. The amazing recoil and large pistol size resulted in the creation of the .40S&W a scant year later.

Certain agencies still use the 10mm, and given the round’s power, it’s not a surprise. That being said, if you’re going to load up with an SMG that shoots a 10mm bullet, you will probably get at least as much oomph out of a 5.56mm or 6.8mm carbine as well.
Ballistic’s Calculator Inputs

Basic inputs for the calculator are as follows, selecting 117mm for the (test) barrel length.

INPUT
180gr 10mm Auto
Chamber Pressure 37500 psi
Barrel bore 10 mm
Case Length 25 mm
Chamber Bore 10 mm
Barrel length 117 mm
Bullet Mass 180 grains
Aspect Ratio 1.8 L/Bore
Burn length 11.6 mm
Projectile Caliber 10 mm
Total Accelerated Mass 180 grains
Expansion Ratio 1.78 expansion
Projectile Load 1

Output Stats

The 10mm Auto is kind of a beast. Sure, it’s not a .44M, mostly. But it’s very powerful, and as there are very few reasons not to carry the most energetic load if you’re carrying one of these at all, I elected to pick more or less the same 180gr bullet used in my .40S&W example, but fired quite a bit faster.

Notes

  • The velocity is at the muzzle. The velocity with a 4.6″ (117mm) test barrel is tuned to match real-world data at 1350fps with a 180gr JHP bullet. This is not the highest energy 10mm available, but it’s pretty close. It gives a good comparison to a .40 on steroids.
  • The breakpoint for pi+ in GURPS is currently at 10mm/.40″. You can see that’s a bit generous, as the bullet modeled would be better at closer to +1 per die. Still, because of that breakpoint, 10mm bullets hit a sweet spot.
Some more notes on barrel length. There are really two practical lengths for pistols here. The 3-4″ set will deliver 3d damage. A full-sized pistol with a 4.5-5″ barrel hits 3d+1. SMG barrels between 6.5 and 9.5″ long will get 4d-1. Unlike the .40, the 10mm continues to gain a bit in damage, with a 9.7-14.5″ barrel turning in 4d. A 16-20″ rifle will hit 4d+1, but beyond that you are into very long weapons.

The JHP with modern design is quite impressive, expanding in this case to 1.77x its starting diameter – and there are commercially-available loads that will expand to a full 2x the starting diameter. The standard load with the 1.78x expansion has an amazing calculated wound channel modifier of 2.4x, making the damage with this load out of a 117mm barrel 2d+2 {2.4} pi, or 3d+1 (0.5) pi++ using RAW. That’s considerably more injury out of a handgun than many or even most 9mm SMGs.

Alternate Loads

If you don’t go heavy and fairly fast, you can go light and ridiculously so. One of the more energetic loads is a 155gr projectile at a blistering 1500fps. This doesn’t really change the stats.

Platforms

For a cartridge that faced very rapid obsolescence at the hands of the .40 “Short and Wimpy”, after the first purpose-built Bren Ten handguns came out, there were a substantial number of quality follow-ons. The Colt Delta Elite and Smith 1076 were big in this chambering, and Glock released their Glock 20 and smaller Glock 29 in 10mm. Both of these were quite large-frame handguns, but in general if you could grip their double-stack .45ACP (the Glock 21), you could hold and shoot their 10mm.

You can get high end firearms in 10mm from such luminaries as Kimber (bout $1,000) or STI ($1600), and these are mostly built on heavy, steel, 1911-style frames.

For SMGs, you seem to have the MP5/10 by H&K, and the MP5/10 by H&K. Seriously. With the right ammo (the fast, light load above) you will still get 4d (0.5) pi++ out of the 225mm barrel, which ain’t all bad.

More pix follow.

Hicks: I wanna introduce you to a personal friend of mine. This is an M41A pulse rifle. Ten millimeter with over-and-under thirty millimeter pump action grenade launcher. 
Hicks: [Hicks hands the rifle to Ripley] Feel the weight. 
Ripley: Okay. What do I do? 

The M41 is iconic. It defines the look and feel of one of the best Aliens movies out there (in my opinion), and was, at least in this scene, treated more like a character than a piece of equipment. 

I recently wrote up the ammunition it supposedly fires as my April Fool’s entry for The Reloading Press. It’s described in the movie as follows:

Ripley: Lieutenant, what do those pulse rifles fire?Gorman: 10 millimeter explosive tip caseless. Standard light-armor-piercing round, why?

Other than the weapon itself, which was made in several non-firing mock-ups and one “hero” weapon that could actually fire blanks, that’s mostly the only information you have on the weapon itself. You do see that loading a fresh magazine gave something like 95 or 99 shots.

This writeup is dedicated to +Kyrinn S. Eis who asked me very nicely to do it.


Screen to Reality Problems


The weapon itself was converted from a .45 Thompson SMG, because the director liked the “angry” flash of the .45ACP cartridge. He wanted the weapon to be impressive when fired.

It was highly modified, obviously, and featured a slung-under grenade launcher that was obviously a converted pump-action shotgun.

It’s got a short barrel for both weapons, making it definitely in the SMG category.

Some of the issues that come up right away have to do with the quoted dimensions of the projectiles. A 12G shotgun is 18.5mm in diameter. The quoted dimension of the grenade launcher in the movie is 30mm, which is nearly twice the bore of the mock-up weapon. As you can see from the UMP in the picture, a 30mm grenade launcher would have been unmistakable. The grenades just aren’t that big.

The second problem – and that’s even before we get to the Colonial Marines’ Technical Manual information – is that the stated 10mm bore size of the rifle runs into issue. Not with the observed barrel opening – that’s probably fine, as the Thompson is, in fact, .45ACP (11.43mm) and larger even than the 10mm caseless claimed.

No, the problem is magazine capacity. A 10mm bullet is . . . wait for it . . . 10mm in width. So if you stack them like they’re in an M1911 pistol (which you’d never do), then 95 of those would be almost a meter long. Basically a three-foot-long magazine. 

Even the 25-round magazine of the UMP above, which protrudes so conspicuously beneath the weapon, is probably about 25cm long, and going from .45 to 10mm might drop that by 10%. Now, it is deceptive – the distance from the barrel to the bottom of the magazine well in the picture is longer than it would appear. And a better graphic shows it as well.

But ultimately, if the magazine is as shown, it will maybe be 7-9″ long – or about 200mm, maybe 225mm. That allows for a maximum stack of 20-22 bullets per column. Let’s be generous and say 25.

Now, you can offset them in width, of course. But ultimately, to get 90-100 bullets out of that magazine for that size, you need four to five columns. Even staggered, four columns will be 36mm wide. Or about 1.4″. Five wide would be 45mm, or 1.75″.

Mostly, though, the magazines are presented as a double-stack configuration, as shown in the replica to the right.

But . . . there’s at least enough room for one more column to the left and right of the double-stack. The movie didn’t show that, but then, there aren’t many quad-stack magazines kicking around for a .45 Thompson. There are plenty of quad-stack mags for assault rifles, though. Well, if not plenty, than some. And since the typical base dimension of an assault rifle round is 9-10mm, having a quad-stack in 10mm . . . even 10mm caseless, isn’t crazed.

OK, so quad-stack. Go us. We’ll still need 24 or 25 bullets tall, though, to get as much as we’d like (95-99 rounds) out of the weapon. But if we allow 200mm tall, perhaps we can get 20, and assume that the spring (if they still use springs in the Colonial Marines) is in the large baseplate of the magazine. In fact, there’s little other reason, except maybe a battery for electric ignition, to have such a large baseplate. That gets us to roughly 80 rounds, with some degree of loss due to poor packing density as four columns go down to two goes down to one.

So maybe 60-70 rounds. The Soviet quad-stack shown was 60 rounds of 5.45x39mm, and that’s fairly respectable, if complex.

The final bit of question comes from a translation from the original source material. The Colonial Marines’ Technical Manual describes the M309 projectile fired by the M41 rifle as a “10x24mm caseless” round. 

Now, that notation is usually something like 9x19mm, where the 19mm is the case length, and the 9mm is the bore of the weapon. So a 10x24mm caseless bullet should have a 24mm area of propellant, and then a protruding bullet. The wonderful (but fake) replicas created by a cosplayer (presumably) with mad skills and plenty of time on their hands seems to do pretty well. The bullet itself, if it’s of similar proportion to a 9mm bullet, will be about 20mm long; a filled explosive bullet may well be longer and lighter density. 

So can the bullets above – 10mm in diameter, perhaps 25-30mm long, explosive filled – be dimensionally correct? The CMTM gives a 210grain bullet, 10mm in diameter. A jacketed lead bullet of 4:1 aspect ratio (like the .308) will have a density (with my program) of 9.3 to 9.9 g/cc. This 210gr, 10mm projectile with a 3:1 ratio – long for a pistol bullet, short for a rifle – will have a density of about 8. It could maybe be stretched to 7.5 (a bit lower than steel) by stretching the aspect ratio to 3.2:1, but any longer than about 3.3 or 3.5 and your bullet is longer than the overall cartridge will be.

Still, the dimensions of the projectile are surprisingly reasonable.

As for the rest, the rifle is supposedly designed around a 247mm barrel, and the projectile develops 840m/s from this length. At high pressures of around 60,000 psi, this powder will remain burning for quite a while down the barrel relative to other designs in my model. So the flash would be impressive. As seen in the movie.

For GURPS, a short barrel like that would likely be Acc 4. 1/2D for a honkin’ projectile like that would be about 425yds, and about a 3,600yd maximum range. Damage at the muzzle would be an impressive 8d-1 pi+.

Oh, and of course, it explodes. I suspect that what this means is that torso hits are treated as vitals hits if it does explode (there’s a note that it doesn’t do well when not fired at body armor in the CMTM), and we pick up a (2) armor divisor due to a penetrating tip or something. RoF is single shot, 4-round burst, or fully automatic.

Recoil should be a beast. The bullet is akin to a .338 Winchester Magnum or .300 Win Mag, which should carry a Rcl of 4 or even higher. If the weapon uses advanced recoil compensation or stabilization, perhaps one could get it down to 2 or 3 (2 is what you’d see from the movie, with the weapon fired from fairly loose grips, which you’d never do with a .308 under full-automatic fire or even burst fire – the M14 was a large weapon and not exactly known for stable full-auto fire.

Rcl that high makes full-auto fire fairly pointless in GURPS; even Rcl 1 or 2 it’s hard to hit with more than one shot. I bet this thing is pretty nasty for suppression fire, though.

Parting Shot

Ultimately, the M41 is a movie weapon that someone took some pains to try and wrap some statistics around, and produced an up-gunned weapon that kicks as hard as a sniper rifle but fires out of a SMG-size weapon. From the hip.

We haven’t talked at all about the grenade launcher, of course. Alliant Tech Systems (now Orbital ATK) tried to get good performance out of a 20mm grenade to no avail – not enough fragmentation, but then they weren’t working with TL9 or TL10 explosives, either. With the right ammuntion, direct fire HEAT from a 20mm weapon isn’t entirely stupid, and with enhanced explosives from the future, is likely the best thought-out part of the entire system.

GURPS does have a pulse-rifle equivalent, by the way, already. Check out the Storm Carbine from GURPS Ultra-Tech.

And of course, while I might cast doubt on the particular combination of velocity, projectile dimensions, and technology, the weapon itself is completely viable. After all, someone went and built one!




The Reloading Press is an at-least-weekly feature here on Gaming Ballistic for 2016. Each week it looks at some interesting real-world cartridges and presents them with hopefully-useful information in GURPS Format.

.44 Magnum/10.9x33mmR

The .44 Magnum is one of the iconic “this is serious business” cartridges both in film and in reality. When you’re packing a handgun that you don’t really care if someone sees you wearing it (open carry allowed, post-apocalyptic wasteland adventuring, or journeying through predator-infested wilderness), and the size of the hole is perceived to matter, this is going to be on the go-to list.

Designed in the 1950s and manufactured from the mid-50s to the present, it was designed as a bigger, badder version of the.44 Special (both of which actually fire bullets of 0.429″ – the 0.44″ spec came from an older method of measurement). 

Until the advent of such beasts as the .454 Casull and the .500 S&W Magnum, this cartridge was the go-to for being able to take any animal or unarmored human anywhere in North America. With some of the largest predatory animals (cape buffalo, Alaskan grizzly) even the .44M might not be considered “enough.”

For everything else . . . “Go ahead. Make my day.”
Ballistic’s Calculator Inputs

Basic inputs for the calculator are as follows, selecting 7.5″ (190.5)mm as the test barrel length, as this was the standard barrel for most of the data.

INPUT
240gr .44M
Chamber Pressure 36000 psi
Barrel bore 10.9 mm
Case Length 32.6 mm
Chamber Bore 10.9 mm
Barrel length 190 mm
Bullet Mass 240 grains
Aspect Ratio 2 L/Bore
Burn length 12.7 mm
Projectile Caliber 10.9 mm
Total Accelerated Mass 240 grains
Expansion Ratio 1.75 expansion
Projectile Load 1
Output Stats
The rated cartridge is a high energy version of a lightweight projectile. It is modeled on a fairly modern 240gr JHP that develops a highly credible 450m/s out of the test barrel. If you’re going to carry a hand cannon in GURPS, you don’t go with the low-energy load! Note that the damage figured given are, nonetheless, for a FMJ round; there will be significant penetration loss with the JHP due to expanded diameter using the model.

Notes
  • The velocity is at the muzzle. The velocity with the 190.5mm test barrel is tuned to match the 450m/s spec with a 240-gr bullet. There are many other loads available, as the .44M is a bit of a handloader’s dream. This was the higher energy of several 240gr loads, but not the highest energy available (detailed in alternate loads, below)
  • Down below about a 2.5-3″ barrel, very small amounts of barrel change can throw the velocity all over the place. While the load information is scaled down to basically the same penetration as the .45 ACP (2d pi+), no one in their right mind would do this. If you’re going to carry a large-frame revolver like this (or the even larger automatic), you don’t tune it down to that level
  • The practical maximum for the barrel is likely less than the 36″ listed by quite a bit. Strenuous opinion on forums put the maximum useful barrel at about 20″ (508mm), with 24″ considered “too long.”
This is a good one size fits all cartridge if you must have something you can put in both a handgun and a rifle and you really want that pi+ rating. A 6-7″ barrel develops a whole lotta penetration and damage

Alternate Loads

Two “alternate” loads will be considered here.

The first is the actual performance of the 240gr JHP out of a 7.5″ and 18.5″ barrel using the data above.

The 240gr JHP will develop 3d+1 pi++ using my model (and 4d (0.5) pi++ using RAW). That’s 11.5 points of penetration for mine, or 7 points for the RAW. Both do high wounding for a handgun. The 18.5″ JHP will do 4d pi++ using my model and 5d (0.5) pi++ by RAW. Penetration is 14 points for the first one, and shy of 9 points for the second. Ironically, discussions about .44M penetration of the PASGT with +Michael Eversberg II recently hinge around this exact point – how robust is the bullet when it meets kevlar?

The other is the big dog. 340 grains of lead flat nose at 1425fps. This will develop 5d-1 penetration out of a 7.5″ barrel, boost the 1/2D range to 580 yards, and with a JHP configuration will deliver 4d pi++ using my model and 5d-1 (0.5) pi++  otherwise. Out of an 18.5″ barrel it’s 6d-1 FMJ and 5d-1 JHP.

Platforms


There are going to be four archetypical platforms here.

The large-frame revolver format made iconic by Dirty Harry. The Smith and Wesson Model 29 has many barrel lengths possible, and the one picture is a bit over 8″ long – 8 3/8″ specifically. That’s a 4d pi++ with JHP, and 5d pi+ with FMJ.

The other big boy for handguns is the Desert Eagle in .44M. 

The Desert Eagle is iconic, perhaps, because film armorers like to use it because it’s massive size shrieks “GUN!” whereas more realistic-sized firearms don’t have quite as much screen presence. The Desert Eagle has 8+1 for magazine capacity, and comes in 6″ and 10″ barrel versions.

.44M Desert Eagle vs Glock 23

The Desert Eagle, because of high cache value as well as rarity, are both expensive and heavy weapons, and very large. Gripping  the Eagle is going to be difficult-to-impossible without very large hands.

Longarm options are mostly rifles, and specifically lever-action rifles are common. This is a “same cartridge for my revolver and my rifle” play, and given how well that this beast does out of a 16-20″ barrel (penetration like an AR15 in FMJ, wounding like a .308) it’s not a bad plan. 

The Marlin 1894 is an example of a lever-action .44M rifle, with a 10-shot tubular magazine and 20″ barrel. It’s available for about $700.

The last would be something like a bolt-action gun in .44M such as this Ruger 77/44. $1100 and 5.3 lbs, with a 4-shot capacity and 18.5″ barrel. Given the attractive choice above with most GURPS-related stats, it’s likely a poor choice for most applications relative to the lever-action gun. I’m sure there are reasons for it – maybe the layout of the Ruger is more amenable to higher accuracy and better (or possible) scope mounting.

The Reloading Press is an at-least-weekly feature here on Gaming Ballistic for 2016. Each week it looks at some interesting real-world cartridges and presents them with hopefully-useful information in GURPS Format.

M309/10x24mm Caseless


The M309 cartridge is the standard ammunition issues to the Colonial Marines in the mid-22nd century, and achieved widespread issue, if not acceptance, by 2179.

The projectile and cartridge are of unusual construction, and many questionable design choices were made in the design and construction of the projectile. This is not unique to the M309 – controversies over ammunition choices have been part-and-parcel of military procurement since the 20th century, if not since the creation of the minie ball.

The basic inputs will be driven from the standard load: the steel-jacketed, 210-grain explosive projectile that is the standard issue to the marines.
Ballistic’s Calculator Inputs

Basic inputs for the calculator are as follows, selecting 247mm as the test barrel length, as this was the basis against which all future designs are compared.

INPUT
M309/10x24mm CLS
Chamber Pressure 58000 psi
Barrel bore 10 mm
Case Length 40 mm
Chamber Bore 11 mm
Barrel length 247 mm
Bullet Mass 210 grains
Aspect Ratio 2.4 L/Bore
Burn length 62 mm
Projectile Caliber 10 mm
Total Accelerated Mass 210 grains
Expansion Ratio 1 expansion
Projectile Load 1

Output Stats

The rated cartridge is the standard projectile, and unusually for a standard cartridge, has applicability from pistol-length to anti-material-rifle length barrels. No doubt this was a selling feature to the appropriation and acquisition boards.

Notes
  • The velocity is at the muzzle. The velocity with the 247mm test barrel is tuned to match the 840m/s spec with a 210-gr bullet. There are many other loads available, but my practice is to take the highest energy commonly listed.
  • As noted, the M309 can find applicability from pistol-length to sniper-length barrels. That being said, the pistol-length configuration develops 2/3 more energy than the M855 projectile from the 20th-21st century, which is also nearly three times the energy of some of the more powerful 10mmAuto rounds, which are their cousins in terms of dimension. Advanced recoil compensation mechanisms and a very heavy base weapon are required to tame the recoil
  • The SMG-length barrel of the M41 Pulse rifle was a controversial choice, as was its standard “magazine in front of the handle” layout, at the time. This configuration still delivers 8d-1 (2) pi+ damage, and if the projectile actually reaches the internal tissue, it explodes, replacing pi+ with an explosive x3 multiplier.
  • The round’s fusing is . . . twitchy at best. If it hits armor and penetrates, it will perform as advertised. If it does not, and strikes clothing, non-rigid armor, or bare flesh, roll 1d. On a roll of 1-3, the round will not explode. Not that 8d-1 pi+ nothing.
The large projectile and heavy bullet make for an interesting design. High energy throughout the range of barrels generally used, a barrel swap (and extended grip) can make for a very useful Designated Marksman configuration with substantially increased penetration. 

Alternate Loads

There are a small number of alternate loads. The most notable is the copper-jacketed M315 “hardball” projectile. With identical ballistics as the M309, this solid round is much, much less expensive than the original – and standard-issue – projectiles. It is hardly less lethal, as well.

XM350 – the competition

Finally, a word must be said about the competition. As noted, the 10x24mm was a controversial choice even at the time, and remains so. The large diameter of the projectile, and fairly low explosive charge, makes the whole idea look good on paper and less so in the hands of the long-suffering troops issued the weapon. The XM350 was a more conventional – and some still maintain superior – choice at the time.

Platforms


As the old movie goes, there really can be only one.

The M41 Pulse rifle was the answer to the question of how the M309 projectile was to be launched. The advertising copy says that the firearm can hold 99 projectiles, which it attempt to accomplish with an (again, controversial) 4-2-1 configuration. The stack is 4 cartridges wide near the magazine base, tapering to two and then a single round at the chamber. This overly-complicated design was made necessary by the observation that a double-stack magazine would be a half-meter long in the desired configuration.

A compact and dense weapon, what it lacks in reliabilty it makes up for in firepower. With a combination of 10mm explosive projetiles and 25mm pump-action grenades, the rifle allows each infantryman to engage light-to-medium armored targets with a wide variety of projectile loads. 

The design process did eventually produce miniaturized recoil-management systems to tame the beastly kick of the original design, to the point where shooters will often fire from the hip, without bracing the weapon on the shoulder.

The Reloading Press is an at-least-weekly feature here on Gaming Ballistic for 2016. Each week it looks at some interesting real-world cartridges and presents them with hopefully-useful information in GURPS Format.

.22 LR/5.6x15mmR

The .22 LR was designed just shy of 1890, as a modification – or at least inspired by – the Flobert BB cap and the .22 S&W of 1857. It was originally a black powder cartridge, and the various loadings and velocities reflect the range from “indoor target use against not-much-other-than-paper” to “wartime use in WW2 in suppressed pistols” to “varmint killin’,” with a lot of plinking and competitive shooting in between.

The fairly low cost and extremely versatile design make it one of the most popular, if not the most popular, chamberings for firearms in the world. The low recoil, high accuracy (remember: Olympics), and general ease of loading and shooting, plus the traditionally low cost (recent shortages in the USA are somewhat of an aberration) make it a great chambering to teach marksmanship, firearms handling, and discipline.

The basic inputs will be driven from the highest energy projectile that’s a standard load: the copper-plated 31gr (2 gram) round-nose bullet fired at 1750fps. This projectile is still less than half the energy of a 9mm.
Ballistic’s Calculator Inputs

Basic inputs for the calculator are as follows, selecting 458mm (18″) for the (test) barrel length.

INPUT
.22LR
Chamber Pressure 25000 psi
Barrel bore 5.6 mm
Case Length 15 mm
Chamber Bore 5.6 mm
Barrel length 458 mm
Bullet Mass 31 grains
Aspect Ratio 1.9 L/Bore
Burn length 10.04 mm
Projectile Caliber 5.6 mm
Total Accelerated Mass 31 grains
Expansion Ratio 1.6 expansion

Output Stats

The rated cartridge is on the higher-energy end of things, but shows behavior that more or less defines the round.

Notes
  • The velocity is at the muzzle. The velocity with the 18″ test barrel is tuned to match the 1750fps for a 31gr bullet. There are many other loads available, but my practice is to take the highest energy commonly listed.
  • The .22LR, even in hollow-point, do not expand enough to give any GURPS benefit for wounding – that is, even a JHP will not expand enough to eke out pi instead of pi-. So the damage is pi- from the muzzle to the limits of range.
The notable features of the .22LR includes the quickness with which the velocity plateaus: once you get to an 11″ barrel, you will not increase velocity enough to get to 2d+1 unless you get to a 31″ barrel . . . and even carefully tuned .22LR projectiles with slow-burning powder, in the real world, start to lose velocity out of a 26″ barrel as pressure starts to decrease faster than barrel friction is increasing. For most standard loads, the longest practical barrel is on the order of 18-19″ (460-480mm).

The literature lists the .22LR as a “150-yard” cartridge. This is due to the transition down to subsonic velocity, and the accuracy degrades measurably from that point. This coincides nicely with the 1/2D range calculated.

This is, was, and always will be an anemic cartridge that is going to depend greatly on shot placement. To the vitals out of a 5″ through 19″ barrel, you can get 6-36 points of damage – plenty enough to kill an unarmored average man. To the skull, you will get 0-40 points, with a fairly low but not unrealistic chance of the bullet deflecting off the skull. 

Anywhere else, you will need to hit a lot. 

Alternate Loads


If you go out and buy a brick of .22LR without some care for getting the maximum energy out of the load, you will likely bring home 40gr projectiles at about 1200fps out of an 18″ barrel. These carry a bit better (1/2D of around 210yds), but do even less damage (1d+2) out of an 18″ barrel. The transition to 2d-1 is at nearly 24″, making it (in reality) top out at the 1d+2 pi- level. It will drop below 1d+2 to 1d+1 at 40-100mm barrel length. So standard .22LR will be 1d+1 out of pocket pistols, and 1d+2 out of rifles.

Very subsonic .22LR exists firing a 60gr bullet at 950fps. This is a 340-yd 1/2D and is about right for 1d+2 pi- at the muzzle of a 18″ rifle. Unlike it’s lightweight cousins, it can expand in JHP format to do pi damage, but base damage drops to 1d+1. Out of a pistol with a 4″ barrel, it will do 1d (0.5) pi as a JHP round, or 1d pi- as a ball round (the copper-washed bullets do not usually qualify as having a metal ‘jacket’ to speak of).

There are snake-shot rounds firing shotshell as well. This is 30grains of #12 shot, each of which weighs about 0.2 grains (!). Wound channel modifier is on the order of 0.1, basically four size modifiers lower than even a pi- round. Penetration is notionally 2d, but this is an artifact of the 1.5mm diameter of the projectile in the model. Best to treat this as RoF 6, 2d (0.2) pi-, clustering groups of pellets together. 

Platforms


There are a vast, vast number of .22LR guns out there. Some classics:

Ruger 10/22 semi-auto rifle. This 18.5″ barrel semi-auto rifle comes in a lot of styles, and is a good plinker for novice and experienced shooters alike. Comes with a 10-round rotary magazine that fits flush with the rifle, or a 25-round box.

In a pistol, the small form factor and low recoil of the round makes it fairly attractive for attaching accessories . . . such as a suppressor. This would include the Walther P22 pictured to the right. This shows a 3.4″ barreled pistol with a suppressor that is as long as the overall firearm itself. 

An unusual .22 LR pistol is the Calico M110, whose helical-fed magazine holds 100 rounds of .22LR. It’s a very unusual looking pistol (and also available in 50- and 100-round capacity as the M950/960 in 9mm) and if you need 100 rounds of .22LR on tap in an otherwise bulky gun, this is what you want. The rifle-length barreled versions are apparently fairly attractive conversions to full-auto, due to low recoil -effectively a precursor to the 4.6x30mm and 5.8x28mm PDW-style weapons with roughly the same projectile weight but using a bottlenecked round to get a lot more energy out of the package.

The concept of the suppressed .22LR has been around for a long time, and saw service as the Ruger High-Standard HDM in WW2. This modified Ruger Mark 1 (and later, Mark II and Mark III) is purpose-built for the role.

Without providing a picture, it should also be noted that conversion kits – often a magazine well insert, a new chamber/barrel, or (in the case of the already-.22″ caliber AR15) simply a new bolt assembly – for many firearms are available, allowing you to swap your usual caliber for the usually less expensive .22LR. This can be especially attractive given that  1,000 rounds of .22LR can be had for $150, while 1,000 rounds of 62-gr M855 style ammo will run about $350-400.