The Reloading Press is an approximately fortnightly (every other week) feature here on Gaming Ballistic that started in 2016. Each article looks at some interesting real-world cartridges and presents them with hopefully-useful information in GURPS format. Except when it’s interrupted by massive writing projects, something interesting should appear every couple of weeks.

6x35mm KAC

The 6x35mm KAC seems to be another reaction to the desire to give folks a short, handy shoulder arm that hits harder than a pistol against what I’ll call “firm” targets. They’re not “soft” targets (unarmored folks in light clothing), nor are they armored behind real cover or wearing Class III or IV level protection. They’ve got soft body armor or clothing thick enough to pose an issue against handguns, or are behind fragile but hard window glass that provides a measure of barrier protection, if a permeable kind.

There’s a lot of information about this round that seems to be classified. It was designed, seemingly, because when you take a round designed to perform well out of a 500mm barrel (the 5.56x45mm) and then chop said barrel down to 200mm, surprise-surprise you get issues. Low muzzle velocity and a fireball and concussion that likely rivals Thor getting frisky with Mjolnir.

So Knight’s Armaments Corp was contracted (or just decided and then got a contract, but I think the design was solicited) to do essentially what I did with the ultra-tech bullet design: take the bullet and the gun and design it all to a purpose: fire something fairly lethal out of a very short rifle. Continue reading “Reloading Press: 6x35mm KAC (many guesses)”

Idle conversation on the Discord chat about a full-auto .50 BMG rifle (as opposed to a machinegun) led to the comment that for sufficiently strong and large races or creatures, they really should be kitted out with battle rifles in sufficiently impressive calibers.

I mean, why wouldn’t a large-enough race make a rifle capable of firing 14.5mm KPV rounds?

Now, it’s been a while, but I don’t think a character’s ST has any impact on a weapon’s stat line.

Let’s look into fixing that. Continue reading “Rcl and ST in GURPS”

Continuing with my exploration of redesigns of the slugthrowers presented in GURPS Ultra-Tech, the next step is to look at submachine guns (SMGs), and Ultra-Tech (sensibly) includes Personal Defense Weapons (PDWs) in this category. However, if one looks at my prior articles, a raw-stats look at the four Ultra-Tech pistols, as well as some heavy design and less-heavy mechanics look at a ground-up TL9 pistol concept, you can see there’s already been some groundwork laid that should influence the following examination.

Prior Art

What concepts have been introduced?

  • TL9 10mm ammo has a base damage of 3d+2 pi+ out of a 4.5″/115mm and delivers around 1,100J of energy
  • There is a family of combustible case 7.8mm ammunition that deliberately targets GURPS breakpoints to deliver 2d+1 pi damage from an 85mm barrel, and 2d+2 pi from a 145mm barrel as a service pistol
  • An integral suppression system probably weighs about 0.1 lbs per 50mm of barrel
  • There’s a high-tech ammo type that was shown as an example of a TL9 combustible case or caseless telescoped cartridge. It uses a long bullet that expands to 75% of the length of the bullet in diameter. Call this CCTAPX (see-tap-ex) for combustible-case telescoped expanding. It’s cost per shot, though, is probalby 10x normal.

What is an SMG/PDW, anyway?

Ultra-Tech uses a fairly conventional classification of weapons, putting SMGs (which it defines as 10mm full-bore pistol rounds from a rifle-shaped platform) and PDWs in one group . . . but classifying short-barreled rifles, the carbine family, along with rifles. Continue reading “GunDay: GURPS Ultra-Tech SMGs and PDWs”

There’s an interesting problem – or at least an observation – when looking at the near-future slugthrowers from GURPS Ultra-Tech. The weapons themselves are a mixed bag of “well, it must be better!” and “there’s hardly any way that can happen.” It’s understandable, but leaving that aside, a futuristic pistol is a problem no matter how you slice it.

Why? The presumption of evolving threats, and a natural asymptote in the evolution of a design that debuted, fundamentally, in around 1900. The broom-handle Mauser C96, the M1900 Browning, and of course the M1911 Colt .45 ACP are all basically TL6 designs that evolved through two tech levels (in GURPS terms) to arrive at the early 21st century darn near as improved as they’re going to get.

Mission

One of the things one has to realize about a pistol is that they’ve always been secondary weapons. They were a one-shot (or even six-shot, in the US Civil War) first-strike to be wielded along side a saber, the primary weapon, initially. Then they were an officer’s weapon or signature, carried by commanders partially in order to remind them that their role was to direct troops, not engage in personal heroics.

Side note: I’m not necessarily making that up. I knew, personally, a Navy SEAL commander who was in Viet Nam. He was the course leader for the McKinsey and Company “mini-MBA,” and a great guy. He was quirky – he went swimming five times a day – but he told great stories, and his charisma and leadership were palpable. Naturally, I engaged him in conversation, and he told me that he rarely (maybe not ever) carried a weapon larger than a pistol, for that exact reason. His troops were there to kill the enemy; he was there to direct his troops. Staring over a gunsight robbed him of strategic vision. Hrm, says I.

But the thing about a pistol is that it’s not a primary weapon. As the old joke goes, “if I were expecting trouble, I’d have brought my rifle.” It’s a defensive or backup weapon that you can have with you all the time. While there’s no question a pistol can seriously kill you, it’s not a “serious” weapon for offensive purposes in nearly any case [1].

So we need to define what the mission of the weapon is. And I’m going to be pretty restrictive about it.

  1. It needs to be something you can carry with you at all times, comfortably. This probably limits total weight and size
  2. In many cases, it needs to be something small enough to carry concealed at all times, and be comfortable doing so
  3. It needs to pose a credible threat to an unarmored person
  4. It needs to be accurate and controllable enough to be used in two or three round salvos; if it’s worth shooting, it’s worth shooting twice
  5. It should hold as many bullets as possible without violating rules 1-4

Note how I don’t say “it should penetrate body armor.” Punching through armor is an offensive task. If you really want to stretch it, you can say that it should potentially be able to incapacitate someone through light armor, and by light we’re probably talking about car doors or casual protection – probably no more than DR 8, maybe even as low as DR 4. If the threat is wearing more than that, you need a rifle.

What does “incapacitate” mean? Heck, it probably means a single vitals hit will make you start rolling for unconsciousness. That’s an average penetrating damage of about 1d+1 pi. Asking a “casual” hit to the torso to do that will put the requirement of base damage in the 3d to 3d+2 range . . . which is 10.5 to 12.5 points of damage. With a pi+ bullet, that’s 2d or 2d+1.

That’s a reasonable ask in either case. Continue reading “The TL9 Pistol – Design Directions (GURPS)”

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. Except when it’s interrupted by a massive writing project, then it’s not every week.

But by special request, here’s the first of several revolver cartridges, which have been sadly neglected on The Reloading Press to date.

.357 Magnum (9x33mmR)



The .357 Magnum was developed in 1934, and the first weapon to chamber it was released in 1935. It was developed in response to the .38 Super (which incidentally was found to penetrate the bulletproof  – bullet-resistant, thanks – vests of the day. That required a faster bullet, as those vests were proof against anything slower than 1,000 fps).

Well, the .357 would eventually far, far eclipse this. More on that in a moment. 

Regardless, this is a very high energy cartridge, and the pressure is about double that of the .38 Special that was the foundation of the design. This led to the case being lengthened by about 3mm to prevent being able to close the cylinder on .38 Special revolvers accidentally loaded with .357M cartridges, which can be counted on to have very poor outcomes to the weapon and the shooter.

The .357 and .38 cartridges both fire 9.07mm bullets (actually .355 to .357″); the .38″ refers to a naming convention used for the outside diameter of the cartridge case.

In any case, this for a long while was the standard reference cartridge by which – rightly or wrongly – all other self-defense and law enforcement cartridges were judged. You can see this in many period writings, and even the more-recent .357 SIG hearkens back to the power (and given the loading below, that is both literal and advertising power) of the .357M harnessed in a conveniently sized automatic platform.

But there’s no question: the .357 is a powerhouse, and revolvers chambered in it with barrel lengths from 4″ to 8″ are bad news if you’re on the wrong end of them. The power is such that they made somewhat-attractive snub-nosed backup guns as well, though having fired one myself, for this purpose a small-frame 9mm is probably a better choice. More on that later.
Ballistic’s Calculator Inputs

Basic inputs for the calculator are as follows, selecting 101.6mm (4″) for the (test) barrel length.

INPUT
125gr .357M
Chamber
Pressure
35000 psi
Barrel
bore
9.1 mm
Case
Length
33 mm
Chamber
Bore
9.1 mm
Barrel
length
101.6 mm
Bullet
Mass
125 grains
Aspect
Ratio
1.7 L/Bore
Burn
length
40 mm
Projectile
Caliber
9.1 mm
Total
Accelerated Mass
125 grains
Expansion
Ratio
1.95 expansion
Projectile
Load
1



Output Stats


The .357M has a lot of chamberings available for it. Everything from about 7 to 12 grams (110 to 158 gr), with the most common seeming to be 125gr and 158gr. Both are available in a wide variety of energy ranges, and some of those energies are shockingly high. The highest energy projectile found develops 1,700fps out of a 4″ barrel. The military 9mm is 124gr and develops 1,250fps out of a 5″ barrel. So yeah, it’s a monster. 

As per usual, I selected the biggest and baddest load to do GURPS stats of, because players will usually gravitate towards this.

Notes

  • The velocity is at the muzzle. The velocity with a 4″ (101.6mm) test barrel is tuned to match real-world data at 1700fps with a 124gr JHP bullet. This might not be the very highest energy .357 available, but it’s likely close.
  • Velocity out of shorter than a 2″ barrel falls off dramatically – you can lose 1d per 2mm of barrel in this range. 
  • The bulk of a .357 cylinder would suggest perhaps going with the 9mm or similar loads actually tuned to deliver performance out of a shorter barrel.
  • I very strongly suspect that the “tipping point” where the propellant charge no longer accelerates the bullet falls rather lower than the 6d damage shown here. This site, “Ballistics by the inch,” shows a 125gr .357M getting the best velocity out of a 16″ barrel, falling from 2000fps down to 1740fps by adding 2″ of barrel. So cutting off damage increases past 16″ of barrel is probably legit.
The very, very good results from 3″ to 16″ barrels make the .357M a versatile cartridge, especially in situations where carrying more than one type is impractical for whatever reason. 

The very, very good results are also a direct result of taking the highest energy I could find. A more reasonable 125gr projectile that is tuned to 1450fps from a 4″ barrel, or a 158gr hunting load at about 1250fps (9mm velocity with a heavier bullet) will both deliver about 3d damage from a 4″ barrel, a 15% reduction. The lower powder burn length required in the model will also tend to tap out the velocity at lower barrel lengths as well.

The JHP with modern design is quite impressive, expanding in this case to 1.95x its starting diameter, or about  17mm – enough to legitimately earn a pi++ modifier. Damage falls to 2d+1 in the model, but 2d+1 pi++ is nothing to sneeze at, being both more penetrating and equally expanding as a .45ACP.

GURPS rules don’t allow that, but the same bullet would do 3d (0.5) pi+. 

So my model would predict 8 points of penetration, and 16 points of injury. GURPS RAW would be 5.25 points of penetration, 15.75 points of injury for the JHP bullets, compared to a flat 10.5 points of penetration and injury for FMJ rounds.

Platforms


The platforms here can be summarized quickly. Sub-nosed revolvers, moderate-barrel revolvers, big-honkin’ barrel revolvers, one or two insane semi-automatic pistols, and lever action carbines.

Starting with the rifle, you can expect a 16″ barrel and 8-round or 10-round capacity, and probably Acc 4 from this. It’s handy and will allow you to get the most possible velocity out of the very effective .357M.

Next comes the semi-auto, which is basically either a 1911-style frame (Coonan sells one), or the venerable and oft-discussed Desert Eagle. We’ve seen the DE before, so I’ll find a picture of the Coonan.

Lastly, we have revolvers in various frame sizes and barrel lengths. The manufacturers (S&W itself in the image shown) have done a nice job of giving options from “beefy” to “svelte.”

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.