H&K MP7A1 versus Ballistic Helmet [High-Tech]

[SimonAce]

Originally Posted by DouglasCole

Here's the basic argument in a nutshell:

M16 round (M193 5.56x45mm, 55gr / 993m/s ) is 1760J, 55gr and 5.6mm.
5.7x28mm SS190 round: 31gr at 715m/s. 514J, 31gr and 5.7mm
4.6x33mm round: 25gr at 725m/s. 420J, 25 gr, and 4.6mm.

Penetration in GURPS (and more or less in real life) goes basically as sqrt(KE), and inversely with the cross section of the bullet, but a much weaker function.

Still, let's look at the first two: the M16 round is 3.42x the energy and basically equal cross section, so the basic damage should be sqrt(3.42) = 1.85 times less. Versus the 5d universally accepted (and well proven through empirical studies) that the M193 round gets out of our M16, the P90 round should be 2.7 dice of damage. That's 2d+2.45, call it 2d+2.

Now, if you've seen the SS190 round, it's POINTY. It's also constructed as an armor piercer, which perhaps makes it eke out something between a 1.5 and 2 armor divisor. Possibly. But I'd expect that of the two bullets, the M16 would be superior. Possibly VERY superior. But it ain't.

I agree with you here. The thing is GURPS kind of abstracts this by giving the 190 round a pistol damage divisor. Maybe its not the best solution but its playable enough

I suspect that if I were to edit GURPS Modern Firepower 4e I'd rate the thing 2d+3 (rounding up instead of down for Tl8 kewl bonus) more or less as you suggested with maybe 3d-1 or 3d in a longer barrel or something ...

This wouldn't be a very effective combat round though -- it would do maybe 3 points on a solid hit (roll of 9+3 /4) -- I suppose this is pretty realistic all things considered, the general gist seems to be this round is pretty impotent a stopper in combat

[ed_209a]

Originally Posted by Fred Brackin

Within it's limited niche the HK is probably a better weapon than the P90 but the "PDW" concept is almost certainly a failure.

You're just not going to issue one of these to everyone who isn't carrying a bigger weapon. It's a specialist's weapon rather than a general purpose one.

I agree it is a niche weapon.

Another possible niche is that of downed aircrew. If you can't manage the bulk of a M4, a PDW lets you at least do some damage to an infantryman in body armor, at some range.

[ed_209a]

I think the Knight's Armament PDW is an interesting take on the PDW.

It's The KA-PDW gets close to the power of a M4 carbine, but in a weapon 3/4 the length and 3/4 the weight.

This is because the 5.56mm wastes a lot of power in a short barrel (like the M4's 14" barrel), and KA's 6x35mm cartridge is specifically designed to get the most out of the PDW'w 10" barrel.

[Ragitsu]

Well, there are hollowpoint rounds, but that somewhat disregards the point of the MP7.

[HANS]

Originally Posted by nick012000

Yes. Helmet has 12 DR, and the gun does an average of 15 damage before damage multipliers are taken into account.

The helmet shown is a PASGT style fragmentation helmet, which should have DR 5 or so . . . going in and out means at least DR 10 to overcome. At an average of 15 points (4d+1), the MP7A1 will go cleanly through, just as depicted, and have 5 points left to do damage -- which due to its pi- modifier won't be much unless you hit the skull or vitals, just like Fackler and other wound ballistics experts say.

Cheers

HANS

[Ragitsu]

Originally Posted by HANS

The helmet shown is a PASGT style fragmentation helmet, which should have DR 5 or so

Hey HANS.

Would you happen to have links or know examples of the DR 12 helmet?

[Phoenix_Dragon]

Also keep in mind that Future Weapons is known for sliiightly over-hyping anything they show as the best thing ever.

[jacobmuller]

DR5 helmet explains a lot - if you want the right answers ask the experts:)
I sincerely hope these guys have the DR12 version
http://www.youtube.com/watch?v=X-VjU...eature=channel

[copeab]

Originally Posted by Phoenix_Dragon

Also keep in mind that Future Weapons is known for sliiightly over-hyping anything they show as the best thing ever.

Not like Billy Mays was the host ...

But yeah, the show tends to be excessively positive about what it covers.

[Ragitsu]

It's one thing to be positive, but another to be dishonest.