How to Stat Ghost in the Shell Style Hypervelocity Ammunition

[GURPS Fox]

So, I've been working on a few settings. One of them has Ghost in the Shell style HV/hypervelocity ammo (which, when loaded into a 9mm Uzi, can cause massive deformations on an armored van and push a cyborg back a good foot, please note that this is with a weapon not designed for such hot loads) which doesn't use electrothermal chemical propellants.

Is there a 3e GURPS answer to this, or do I have to cook one up?

[johndallman]

Don't try to explain how this works in-setting. You can't get it to make physical sense.

The effects seem to be increased damage, plus drastically increased knockback.

[hal]

Damage is a function of mass x. Velocity. Deforming armor is simply rigid armor giving way to the impact. Ask me to take a commercial cartridge from CARTRIDGES OF THE WORLD, and I can list the weight and muzzle velocity of said cartridges. For a hyper velocity round, if it is chemically based, it matters not if the propellant is solid or liquid inside the cartridge - the stored energy is what matters.

Either lower the projectile mass, or increase the propellant energy (or both) to increase the muzzle speed of your hyper velocity round.

What kind of damage are you looking to see with your round?

[Fred Brackin]

Originally Posted by GURPS Fox

.

Is there a 3e GURPS answer to this, or do I have to cook one up?

At least 3e did have bullet Knockback though it was a 30pts of damage or slightly more than triple regular Uzi damage of 3D-1.

At least propelling 9mm bullets at 3x velocity is possible. It'd make the gun blow up but it's possible to make the bullets go that fast.

I know you don't want to hear about realism so you only give the ammo a chance (say 9 or less) to make the gun blow up.

Oh wait, is that cyborg being pushed back by _firing_ the gun? That's just more Rcl.

[The_Ryujin]

I just treat it as Extra-Powerful Ammunition, High-Tech p. 165. Here's my take on the manga version of the C-25A.

[mburr0003]

Originally Posted by johndallman

Don't try to explain how this works in-setting. You can't get it to make physical sense.

The effects seem to be increased damage, plus drastically increased knockback.

I would also have an 'escalating' Malfunction rate in weapons not designed to fire these hot-loads. Say start at Malf 17 and just decrement at whatever rate feels best to represent the extreme material stress the firearm is under.

[Donny Brook]

Sounds like flat-head rounds with some kind of secondary drive system.

I'd give them double knock-back and a split-damage effect (lower at short ranges).

[Ulzgoroth]

Originally Posted by Donny Brook

Sounds like flat-head rounds with some kind of secondary drive system.

I'd give them double knock-back and a split-damage effect (lower at short ranges).

I don't think being bad at penetrating armor is an intended element, though. Even if the depiction does come off that way somewhat.

[GURPS Fox]

Originally Posted by The_Ryujin

I just treat it as Extra-Powerful Ammunition, High-Tech p. 165. Here's my take on the manga version of the C-25A.

So, how would you do that stat-mod-wise?

Originally Posted by mburr0003

I would also have an 'escalating' Malfunction rate in weapons not designed to fire these hot-loads. Say start at Malf 17 and just decrement at whatever rate feels best to represent the extreme material stress the firearm is under.

The Uzi in the movie in question was beyond wrecked after firing a magazine of the round type. Frame, barrel, firing block, all busted. Implied that he was lucky that it didn't go off in the perp's hand. Weapons designed for such ammunition can go for a while using said ammunition.

Originally Posted by Ulzgoroth

I don't think being bad at penetrating armor is an intended element, though. Even if the depiction does come off that way somewhat.

More like just how ridiculous GitS materials tech is. They've got CNT muscles that can make jumping between buildings to get high plausible, and drops of 200+ meters be a cakewalk...

[The_Ryujin]

Multiply damage and range by 1.1×, cost by 1.5×. they're probably at lest APHC, add AD (2) and reduce pi damage down one category, cost 2×. For my write up I used a hypothetical Armor Piercing Dense Cored round triples cost but does everything that APHC does and increase damage by 1.2×.