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.
The 9x19mm was invented by Luger in 1902. It is perhaps the most widely used pistol cartridge worldwide, and with recent advances in hollow-point ammunition reliability, is poised to reclaim its former spot as the issue cartridge of the FBI over the .40S&W.
There are many loads for the pistol, but the most common seem to be the 115gr, 124gr, and 147gr loads. They are usually available in full metal jacket (FMJ) and various flavors of hollow point. From a GURPS perspective, the most important load is probably the 124gr NATO standard round – an 8 gram bullet fired at 1250 fps from a 5″ barrel – it’s the standard for 2d+2 as well as pi pistol rounds. A reference bullet, so to speak, defined as doing both 9 points of penetration and 9 points of injury.
So we’ll work that one up, and then talk about variations.
Ballistic’s Calculator Inputs
Basic inputs for the calculator are as follows, selecting 127mm for the (test) barrel length.
|Total Accelerated Mass||124||grains|
- The velocity is at the muzzle. The velocity with a 5″ test barrel is tuned to match real-world data at 1250fps, for NATO standard ammo. This is not the highest energy 9mm available, but it is the standard GURPS 2d+2 pi bullet, so it’s what I chose.
- 1250 fps is pretty good for a 9mm load, though – not that you can’t get more, but in self-defense loads (JHP), the fastest 124gr tested at this site was slower than the standard FMJ NATO load.
- There is no pi to pi- range; this bullet does not gain appreciable wounding by tumbling.
Now, for SMGs you can get longer barrels – but not as long as you might think. The MP5K has only a 4.5″ barrel (2d+2) but can hold a lot of bullets and fires them quickly. The more robust MP5 is 225mm for the longest barrel, which only ekes out 3d-1. To get to the full 3d you’ll need/want a 9.5″ barrel, but you can’t get to 3d+1 until you’re over 450mm. Even the Beretta Cx4 Storm is only 422mm – most carbines seem to like to come in 16″ barrels or smaller (3d), but the Citadel M1 does come with an 18″ barrel that should deliver about 3d+1. Of course, if you are toting a 35″ weapon around, you can do a lot better than that for damage, ammo weight, etc with a 5.56x45mm carbine or even a full-size rifle in a bullpup. The reason you do this (carbine in 9mm) is for Accuracy, not damage.
As noted earlier, the more common loads than the military one will be hollow points. That being said, there are slightly hotter 124gr FMJ loads, the hottest I could find only being 1310fps, which my model gives as being achieved at about 36,200psi input. That gives 9.8 points of damage, which is enough to eke out 3d-1 pi.
Alternate loads tend to be alternate weights, with a lot of 115gr stuff being available as very high velocity rounds, especially from SMGs, and 147gr heavy bullets from pistols, both of which are available in JHP. The heavier bullets will tend subsonic, which makes them excellent for platforms like the MP5SD6 – an integrally suppressed weapon.
Some of the best JHP will expand to as much as 0.6 to 0.7″ in diameter, which is roughly double what the starting diameter is. That’s very good, and more typical of JSP rifle rounds – which have a lot more body to work with.
That means a proper JHP round really earns it’s pi+ rating. The GURPS rules give JHP ammo a (0.5) armor divisor. The more accurate way to do it is to subtract 1 point of penetration per die. Lo and behold, this makes the best 9mm hollow point from the prior web page (1170fps and 0.66″ expansion, the Golden Saber +P loads) provide 2d pi+, which is the same penetration and injury as a .45 ACP, but with a heck of a lot more shots per magazine and less recoil.
Pocket pistols with a 2.5″ barrel that would include derringers and small concelable pistols like the Kahr and other 9mm models. These will often hold fewer than 10 rounds.
Concealed carry pistols with a 3-3.5″ barrel that are “commander-sized,” which means small and easy to carry, but likely double-stack weapons that will hold over a dozen shots, perhaps closer to 15.
Full-sized service pistols with 4-5″ barrels. These will hold 15-18 shots in the magazine.
SMGs and Carbines with 9″ to as high as 16″ barrels. Nearly all will do about 3d-1 or 3d pi damage, and with the right hollow-point round will deliver 2d+2 pi+, which is a good reason to carry one (still not as good a reason as to carry a carbine with an assault rifle chambering for many reasons).
As noted above, subsonic 9mm is good for suppressed weapons, the most famous of which is probably the MP5SD series.