The Reloading Press was a feature that ran steady for a while here on GB, but I lost track of it when I got busy publishing. But recently, I’ve been hearing noises about a new “best cartridge ever.” Well, that’s what nearly all new cartridge promise. Even so, this one was very interesting, and it combines two features I like – and that GURPS likes – in one place. A long, narrow, high sectional density bullet, plus a shorter, fatter case which gives a nice starting volume to keep pressure high.
.224 Valkyrie (5.7x41mm)
The .224 Valkyrie takes the basic case in one of my favorite cartridges for GURPS (and not bad in real life, too), the 6.8x43mm SPC, and then launches a long, narrow bullet from it with the same barrel diameter as the base .223/5.56x45mm NATO bullet.
It was developed in 2017, and really looks an awful lot like someone was playing with the GURPS ballistics calculator I developed. They weren’t, of course, but . . . well, see for yourself.
The basic concept takes a normal 6.8SPC case and launches a very heavy, long .223 bullet out of it. The standard load is 90 grains, whereas a usual match-grade or longer range .223 is 69 to 77 grains (depending on manufacturer). So this is going to be a bullet that really wants to not slow down . . . and you bet, one of the intended uses for the .224 Valkyrie is to ring bells to 1,000m while still remaining supersonic, which is about 350m/s.
The usual contender, the 62gr M855, or the improved Mk318 or M855A1, fall to the speed of sound at about 570m using my calculator, which says “accurate to 500-600m” out of the shorter barrel weapons that’s their design platform, and about 630m out of a 20″ barrel.
So what happens when you fling a 90 grain bullet out of a 20″ barrel? Nice things.
Ballistic’s Calculator Inputs
Basic inputs for the calculator are as follows, selecting 406mm for the barrel length.
| INPUT |
|
|
|
.224 Valkyrie |
|
| Chamber Pressure |
55000 |
psi |
| Barrel bore |
5.7 |
mm |
| Case Length |
41 |
mm |
| Chamber Bore |
10.7 |
mm |
| Barrel length |
508 |
mm |
| Bullet Mass |
90 |
grains |
| Aspect Ratio |
5.4 |
L/Bore |
| Burn length |
14.66 |
mm |
| Projectile Caliber |
5.7 |
mm |
| Total Accelerated Mass |
90 |
grains |
| Expansion Ratio |
2 |
expansion |
| Projectile Load |
1 |
|
|
|
|
Output Stats
The rifle develops appreciable damage at pistol-length barrels, at least within the assumptions of the calculator. Why you would want to do this is another question, and putting all of that powder out of a 5″ (127mm) barrel is an exercise in gratuitous fireball generation (OK, maybe that’s why you’d want to do it).
At longer barrels – which is the entire point of the round – it comes into its own. Out of a 14.5mm carbine barrel, it’s still going to hit for 5d or 5d+1 and stay supersonic to 750m. With a target rifle of 20 to 24″, the calculator suggests nearly 6d penetration and an accurate range pushing 850m…and it will tumble and fragment (and not drop down to pi- instead of pi) to 220m out of a carbine and 320m out of a rifle-length platform. And that’s no joke.
Real-world data, rather than my calculator, pushes that supersonic distance to something like 1,250m with the right barrel and bullet. This thing can reach a long, long way. (Max range, not shown, is probably 4,550m with my calculator.).
So, here’s the chart:
| Half-Damage Range |
661 |
|
|
|
|
|
|
| AP Wound Channel |
0.5 |
|
|
|
|
|
|
| Normal Channel |
1.4 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Barrel Length(mm) |
Barrel Length (in) |
Velocity (m/s) |
Muzzle Energy (J) |
Damage |
D&D Damage |
Supersonic (m) |
Pi to pi- (m) |
| 117 |
4.6 |
475 |
658 |
3d+1 |
16 |
303 |
0 |
| 137 |
5.4 |
516 |
777 |
3d+2 |
17 |
385 |
0 |
| 160 |
6.3 |
555 |
899 |
3d+3 |
17 |
458 |
0 |
| 174.5 |
6.9 |
577 |
971 |
4d |
17 |
496 |
0 |
| 204 |
8.0 |
615 |
1104 |
4d+1 |
17 |
559 |
25 |
| 241 |
9.5 |
655 |
1251 |
4d+2 |
18 |
622 |
87 |
| 285 |
11.2 |
694 |
1406 |
4d+3 |
18 |
680 |
145 |
| 311 |
12.2 |
714 |
1488 |
5d |
18 |
708 |
173 |
| 364 |
14.3 |
750 |
1640 |
5d+1 |
18 |
756 |
221 |
| 442 |
17.4 |
793 |
1834 |
5d+2 |
19 |
811 |
277 |
| 524 |
20.6 |
830 |
2007 |
5d+3 |
19 |
856 |
321 |
| 577 |
22.7 |
850 |
2107 |
6d |
19 |
880 |
345 |
| 700 |
27.6 |
890 |
2311 |
6d+1 |
19 |
926 |
391 |
Notes
- The velocity is at the muzzle. The velocity with a 20″ barrel is tuned to match real-world data at 2700 fps, which is the long, heavy bullet designed to carry farther, rather than develop the most energy at the muzzle.
- The pi to pi- range is where the damage drops from piercing to small piercing. For very short barrels (smaller than 177mm in my model), the bullet is slow enough that it will not yaw and fragment, and so it’s only good for pi- rather than pi. This is defined as 600m/s in my model, which is somewhat arbitrary.
- It’s possible that the damage (penetration, really) is perhaps 10% high. That would still give a 20″ barrel about 5d+2, and a 14.5″ barrel a full 5d out of an M4 platform.
At any useful barrel length for a rifle cartridge, that is, about 9″ and higher (and that’s a darn short rifle), there is some range at which it will do its full pi damage type. At carbine length and above (14.5″) this is measured in hundreds of meters; this is a good choice at moderate range as well as long.
For GURPS gunners, it’s a good cartridge, though not a great one, I think. The long range is short-changed in the calculator vs reality, and the difference between (say) a 320m range where it drops to pi- and a 660m 1/2D range is pretty far beyond the usual engagement distances for PCs. You do get rifle-size penetration out of a carbine-sized platform, though, which is nice. I suspect recoil is manageable as well.
Where this will do well is if you don’t want to lug around an 9-11 lb rifle in the form of a .308, which has a lower tumble range (250m) and a lower 1/2D range (575m) than the 320m and 660m of the .224 Valkyrie. If the 7.62 actually drops from pi to pi- when it drops below 600m/s or so, then there’s a weird case where at 250-350m, and then between 575 and 660m you’re better off with the .224 Valkyrie, but at other ranges you’re better off injury-wise with the .308. That’s cutting it pretty fine: what in general this means is that with a full-length rifle in both cases, you can go with a lighter platform (AR15 rather than FN-FAL, AR-10 based). That can save you three to five pounds on your arms. Also, the ammunition is lighter and the magazines bigger for the .224 Valkyrie.
For GURPS, though, you really need to care about reaching out a long, long way with a lightweight weapon before this becomes something you’re looking at seriously. Ironically, where the
6.8SPC got somewhat of a “meh” reaction in the real world, in GURPS it’s like the .40S&W – a goldilocks cartridge where everything is “just right.” At 6d it’ll drop Joe Average to -HP in one shot, and 3d to the vitals at distance is still a potential lethal dose through light body armor.
Platforms
You need a purpose-built upper receiver (or at least a barrel, chamber, and bolt change) to shoot this cartridge. The thing is going to look like every other AR-15 style rifle out there on the outside, and you’ll spend (in 2019) anywhere from $350 to 700 to get one…unless for whatever reason you want/need to spend more (for things like super-custom, which is frequently a great excuse to buy Weapon Bond).
So no real details or special platform list today! This modification gives you a bit more penetration, a bit more range, and a bit heavier ammunition out of a barrel that’s the same bore as a standard M16/AR15. It does this by increasing the size of the cartridge case, which keeps the pressure higher as the bullet goes down the barrel, and by shooting a round that’s probably going to be 50% heavier than the one you launch out of your standard M16 type platform. For carbine users, this is a good thing, in a way, because it retains its full damage 50% farther than the lighter round (though both have roughly the same 220m or so range to where they both drop to pi- from pi).
