Armor, Hit locations, and math Options

[Eryk the Red]

I'm not really into injecting bonus realism into my Shadowrun much, but this stuff is actually really neat. If I were to start a new campaign, I'd likely modify the weapon stats based on this stuff, simply because it makes them more interesting.

(I wouldn't likely add the hit location stuff, because I don't want to make more work for myself during combats.)

[Crusher Bob]

I'm not really advocating the hit location system either, but created the system to expose more 'design knobs'. This way, if someone decides they want to alter the system further, they can take a look at all the bits that went into making it.

[Eryk the Red]

I never really understand why the RAW weapons all have such weak AP values. There's room for greater weapon variation, but instead you just have this progression of "higher DV and better AP". I like this way better, where a rifle might have a close DV to a pistol, but much better penetration.

[Crusher Bob]

Vehicles and armor:

How much armor should that vehicle have?

Are the weapons modeled right so that the right kind for feel is preserved?

In general, people measure vehicle armor as the amount of
rolled homogeneous armor (RHA) it is equivalent to. While anti-vehicular weapons are likewise measured by the amount of RHA that they can penetrate.

Sample armor thicknesses:

Armored limo/executive protection style armored sedan: 9-12mm RHA (good vs pistols and some rifles)

Cash transport type armored car/armored humvee/police type armored vehicle: 15mm RHA (good vs rifle fire)

Lightly armored APC (M113) 25mm RHA

Heavy armored APC/IFC (Bradley, BMP3) (40+mm RHA front, 30+mm Sides, 25mm Rear)

Light Tank/Armored car/Obsolete MBT (200+mmRHA front, 80+mm RHA sides, 25+mm RHA rear)

Modern MBT (600+RHA front, 200+mm RHA sides, 80+mm RHA rear)

Armor penetration of bullets:

SS109 5.56mm (probably armor piercing in SR4) 12mm

M993 7.62mm AP 18 mm

12.7x99mm (50 BMG) (Heavy machinegun and Anti-material rifle round) 19+mm

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It looks like we got luck and we can approximate the amount of RHA that a bullet in SR4 will penetrate by comparing it's penetration total (damage - ap value) to mm in RHA. This highly overrates pisotl rounds, but the rifle rounds and the HMG rounds seem to be in about the right place.

Once you get higher that HMG rounds in your SR game, you are probably better off just not rolling damage.

[Moon-Hawk]

[Eryk the Red]

I haven't done the math, but I think weapons with significant AP values have a better chance of doing damage that doesn't destroy outright. And if you re-stat weapons in the way that's been discussed in this thread, it might work alright as is. But someone would have to do the math to figure that out.

[Moon-Hawk]

[Crusher Bob]

Firing AP HMG rounds (7 (-16)) at an APC
[edit, sigh had to reduce APC armor to 24 so that a single round would get through]
(24 armor, 12 body):
1 round with 1.5 hits
Damage 8.5 (-16), leaving 8 armor
20 dice to soak get 6.67 hits, leaving 1.83 damage.

Same round vs armored limo
(armor 12, 6? body)
damage 8.5 -16, leaving no armor.
6 soak dice get 2 hits, damage 6.5

The trick is to have the actual damage value take only a fraction of the penetration value. This makes it more survivable for characters, means that you roll less dice when you actually have to soak something, and lets you control damage vs armor a bit better.

Sample LAW vs light armor
The M72 LAW penetrates something like 350mm RHA. If we bothered to give it a damage code something like 35 (-315) might do.

The APC is toast (taking 32.5 damage) [edit here, was 34.5]

A light tank with 300mm RHA on the front and around 36 body (has 26 hits?).
The AP value of the LAW negates the tank's 300 armor on the front, leaving 36.5 damage to be soaked by 36 body. The tank gets 12 hits and takes 24.5 damage.

Second light tank
The enterprising tankers have added some sandbags to the front of the tank, being worth another 50mm of RHA vs HEAT rounds.
The LAW barely penetrates (penetration 351.5 vs armor 350). The extra armor gives the tank another 35 dice (350 armor - 315 AP value = 35) to roll for resistance. This means that the tank only takes around 12.83 damage.

LAW vs side of MBT
We'll give our MBT armor 300 on the side and 60 body. (38 hits?) So we are looking at 36.5 damage vs 60 soak. The tank takes 16.5 damage.

While this is not really ideal, it probably models heavy vehicles and weapons good enough for most SR games.

[edit 2, will throw in tank gun vs. tank's frontal armor]
Tanks frontal armor 600, body 60, condition monitor 38 hits

Tank gun (penetrated 650mm RHA) 65 (-585)
Hits with 1.5 successes.

Damage 66.5 vs body 60 + 15 armor (75 total soak, 25 hits on soak). Tank takes 41.5.

From a longer range band, the tank gun only penetrates 600mm RHA (60 (-540)
With 1.5 hits, this is still enough to penetrate the tank.

Damage 66.5 vs body 60 + 60 armor (120 total soak, 40 hits). Tank takes 26.5 damage.

This post has been edited by Crusher Bob: Aug 14 2007, 01:35 PM

[Crusher Bob]

Some more in depth numbers, to be sure that things are working out:

Vehicles:

[Crusher Bob]

If you want additional complexity in heavy weapons then we need to account for some additional stuff:

Penetration decrease over range
The armor penetration of KE based weapons decreases significantly over range. Of course, this generally only matters for targets significantly further away than 500 meters...

HEAT resistant composite armor/Explosive reactive armor
If you are going to model the extra HEAT resistance of composite armor/ERA then you'd need to fiddle with the damage of the HEAT based weapons some.

As a sample, the MBT with composite armor would rate something like 1200/600/200 vs HEAT attacks and 600/300/100 vs KE attacks and an ERA equiped MBT might have an extra 300mm RHA equivalent on the front.

If you are going to do that though, you'd need to model top attack and tandem charge attacks... and most people will not be interested in that kind of detail.

[Crusher Bob]

Heh, can't let my wanking thread fall off the first page. :) If any of you are reading, please weight in on some of the system questions.

Should stun damage be soaked with BOD + WIL? There should be some 'penalty' for having damage converted to stun, but how to implement it?

Did anyone want more complex modeling of heavy vehicles and their armor?

Any gimmik weapons you'd want to see modeled? (HK MP7? .458 SOCOM?, 5.56mm Steyr Flechette?)

Shotguns
We'll use as our two points for comparison 7.62 NATO firing expanding rounds 7(-2) and 50 BMG 8(-12). Buckshot rounds produce massive injuries, so we'll start with a base damage of 8, but buckshot won't penetrate armor very well. AS the heavy pistol has a penetration value of 6, we'll guess buckshot should rate around a 5. This would make buckshot do 8(+3). This makes shot mostly useful for killing unarmored targets and blowing doors open.

Shotgun slugs.
We'll give slugs a base damage of 7. It looks like IIIA armor will stop most slugs which implies that the total penetration of slugs should be no more than 9. If we give slugs an armor penetration of (-2) that would make the final damage code 7(-2) making them generally identical to expanding 7.62 NATO (but have a much shorter range). This doesn't fell quite right, but there not a whole lot of wiggle room left in the numbers.

Buffalo rifles
Since they included the elephant gun in the basic equipment list of SR4, better come up with some numbers here. Since 50 BMG does 8(-12) we'll stat up the buffalo rifle as doing 8 but having much lower penetration. 8(-3) might do the job.

Grenades
This one will present some difficulty. Armor provides significant protection from shrapnel, which means that someone in any of the armored suits would be highly resistant to any shrapnel based attack. In addition, there's the game mechanics worries about how to reflect successes to hit in increasing grenade damage.

In addition, there is a significant difference between the power of hand grenades vs launched grenades. (The hand grenades are considerably heavier, packing more explosives and more fragments).

So I'll try to model three different sizes of grenades:
Hand Grenade
Fragmentation type
Damage 12(+6) -1 damage/meter
Offensive/Concussion type
Damage 10 -2 damage/meter
Large launched grenade (40mm)
High Explosive Dual-Purpose type
vs armor: 12 (-36) (direct impact vs vehicle)
+ fragments 10 (+6) -1 damage/meter
Small launched grenade (25mm)
All the multi-round underbarrel GLs fire this type.
High Explosive Dual-Purpose type
vs armor: 9 (-27) (direct impact vs vehicle)
+ fragments 8 (+6) -1 damage/meter

This means that grenades have greatly degraded utility vs anyone in heavy armor (14-17 dice) will be highly resistant to grenades.

As a quick fix for resistance to grenades vs placement, I'd try explosions are soaked with BODY + REA as long as you have the ability to get out of the way (are not restrained or surprised). Adding movement modifiers may also be worth a look: so target was running +2, target was walking +1 (penalty for being stationary?). And bonuses for having the grenade going off on the other side of the cover you are behind (+1 to +6).

Example:
Helmet Bob (armor 3, body 3, reaction 3) is hiding behind a wall (cover +4) when a grenade goes off right on the other dice. he 12 damage with body 3 + rea 3 + cover 4 + armor 9 for a total of 19 dice. This gets him around 6.33 hits, meaning he takes 5.67 damage. Had he been in the open, he would have only rolled 15 dice for soak and taken 7 damage. Had he not been wearing hit helmet, the damage would have gone up by another 3 points.

A Bob in heavier armor (total armor 14) in the same situation (behind cover) would have only taken 2 points of damage.

This may weaken grenades a bit too much (especially compared to area of effect spells), so some more tinkering is warranted. Any suggestions?

[Eryk the Red]

About Body + Will resisting stun, I don't think that should be the blanket rule. I think Willpower should add to damage resistance when armor is not penetrated. (Whether the damage was originally Stun or Physical.) This is a game balance preference, more than anything.

[Crusher Bob]

Hmm, how about just reducing the damage by 1 point if it was converted to stun? Keeps you from needing to roll anything and makes the change in damage specifically part of the 'convert to stun' process.

[darthmord]

Feel free to model the MP7.

I really need to see if I can legally purchase one in RL. Might have to special order it such that it's modified to not support FA.

[Crusher Bob]

Might as well model the whole family os such arms

Starting with the slivergun replacement

All assumed to be firing AP ammunition already. If you want to implement velocity control for silencer, the performance drops through the floor (reduce AP value by 6 or so).

pistol
(FN57/slivergun)
damage 2 (-8)
magazine 24 rounds
SA/BF
gas vent/2

machine pistol
(HK MP7)
damage 2 (-8)
magazine 40 rounds
SA/BF/FA
Intergral 2pts recoil comp?

sub-machine gun
(FN P90)
damage 3(-8)
magazine 50 rounds
SA/BF/FA
Intergral 2pts recoil comp?

Assault Rifle
(steyr ACR )
Damage 3 (-13)
(hmm, what to give it for mag capacity)
magazine 60? rounds
SA/BF/FA
Intergral 2pts recoil comp?

The ACR is the real loser here, you have to be shooting at someone in heavy armor for it to do better than a basic assault rifle.

[darthmord]

Hey Bob, got some info for ya...

Per the manufacturer website the MP 7 only does SA & FA. It also supports 20 and 40 round magazines.

Also, saw a demo of it on Future Weapons and it penetrates NATO standard armor with the standard ammo (4. something mm rounds). In fact, the helmet he was shooting at, the round penetrated the front of the helmet and exited the back. Exit hole was about the size of a quarter (25 cent coin).

[Crusher Bob]

These are not exact copies of the real world guns. I gave all of them the SA/B/FA option since SR does not allow firing short bursts from FA only weapons. THe helmets are only rated as IIIA armor. Since the MP7 has penetration stats that are the same as an assault rifle (both are pen 10) it will also penetrate the helmet.

Since SR4 does not have complex concealability, modeling the 20 round magazine for the MP7 like weapon doesn't have much point. Using the shorter magazine won't make it as concealable as a heavy pistol, so why bother?

I'll throw in the various integrally silenced weapons as well:

Assault Rifle
(.300 whisper)
Damage 6(-2)
magazine 30 rounds
SA/BF/FA
Intergral 2pts recoil comp?
Silencer
Sigh, SMG ranges are too short, but maybe you should use them instead of AR ranges.

Sniper Rifle
(VSSK or .50 whisper rifle)
Damage 7(-4)?
magazine 5 rounds
SA
Silencer
Use assault rifle ranges

[Crusher Bob]

Evolution in armor and weapons.

One of the problems you'll run into designing games set in the future is that the systems you develop are not 'fully evolved'. So some weapons don't have a counter, or some armor is unbeatable, or some clever combination of stuff from thing X and thing Y giv you an unbeatable advantage.

You can see the evolution of weapons systems pretty clearly if you watch things. For examples, the development of the Wild Weasel doctrine to counter SAMs deployed in Vietnam.

An additional problem in game design is that you never want the character to become determined only by the equipment he carries. So, we don't want the combat in the game to revolve around who has the latest series of combat nanites, with whoever doesn't being killed so fast that they didn't even have time to notice their death.

The other game design problem is that certain things are quite difficult to model without every player having an in depth knowledge of the actual thing being modeled. See for example, and in brief guide to BVR (beyond visual range air to air) tactics try A nuggets guide for a quick sampler (look for the section that starts with when to use the Jammer).

So, for example, how do you address stuff like composite armor (chobham) and its relatives), top attack ATGMs, active anti-missile defenses (Arena and it's relatives), electrical/capcitor based anti-HEAT systems, or whatever the newest thing is? They'll have those in the future, right?

Remember that your final system has to be gamable. Unless you want to spend all your time thinking of all possible uses for a tech and it's counters, you either reduce it to two opposing rolls of the dice or just leave it out.

If you can find it, The old game Prefect from FASA has a pretty good sample of thinking about the ramifications of the technology. There's a bunch of neat stuff about how to fight with armies of flying tanks that you can drop from orbit, and some other stuff.

For a look at the 'just reduce it to opposing dice school' take a look at how Dirtside II (available here for free) handles missiles and missile defenses.

So how about composite armor?
The unit database in Tacops4 gives you some reasonable data for the RHA equivalent values of tanks equiped with both composite armor and ERA panels.

Assuming our sample tank of 600/300/100 was equiped with composite armor, giving it the 1200/500/150 vs HEAT attacks would no be out of line. While adding ERA panels to the front might give it 900 RHA equivalent vs HEAT. (much better data can be had out of the tacops unit DB).

So what about top attack missiles?
Currently, the top attack missiles are much newer than the tanks. This means that the current generation of tanks was not designed with top attack missiles in mind.

Sign, have some stuff to do, will come back later.

[Thufar_Hawat]

Hi Bob

Just like to say that this is just what i'm looking for my game. Been using hit locations for a while now and this ties in very nicely.

Especially like what you have done with the heavier vehicles and the weapons to take them out, as there was a huge problem with them under current game mechanics (not a scratch or Dead no in between).

Great set of house rules.

Have you thought about melee combat and impact armour? I see you are now using ballistic armour for resisting grenade damage.

Ash

[Thufar_Hawat]

First off, sorry for reviving an old thread.

Bob, have you done any more work on this idea, specifically:

Have you put any thought into using this system with melee weapons and hand to hand in general? Would you keep a separate impact armour rating system.

At first i thought you could get rid of impact armour all together, but on reflection there are real world armours that are very effective against knives, and also padded armour for use against batons that would not stop any but the lightest bullets.

I;ve been using these rules with my own hit location system for a while know and it seems to be working really well. I love the way you've modeled vehicle armour and anti-vehicle weapons.

If you have any more musing's on this subject i'd love to hear them.

Ash

[WearzManySkins]

@Bob
Shotguns
Have you seen the AA 12 shotgun, and the various ammo it fires?

http://www.camo-store.com/auto_assault_12_...bat_shotgun.htm
http://www.armedforcesjournal.com/blackwat...r/?s=2005_main1
http://www.youtube.com/watch?v=g77sLmw-UcY

WMS

[Redjack]

[WearzManySkins]

@Redjack and Bob
OK here is some shots of the Kriss Prototype .45 cal SMG

http://world.guns.ru/smg/smg96-e.htm
http://www.youtube.com/watch?v=f2kEg8rEPl8
http://www.youtube.com/watch?v=DsvbNfmBjQ0...related&search=

WMS

[Hartbaine]

FFS people... go outside, get laid...

Here's my math to contribution:

GM says "Yes, you can hit that location." 100% probability for a called shot.
GM says "No, you cannot hit that location." 0% probability for a called shot.

Great work however, and I'll prolly end up using it once or twice, heh. :P

[Wounded Ronin]