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Armour penetration and firearms

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Im doing a top-down 2d rpg with simplistic combat. Think "a link to the past" meets "fallout". Enemies have different HP and are either armoured or non-armoured (all armour work the same way, there is hardened non-humans and humans with kevlar for example).


I need a simple way to determine how different weapons interact with armour. I want it to be easy to understand yet (if possible without compromising gameplay) logical in terms of how real weapons work. I know penetration differs wildly when it comes to range to the target but i cannot take that into consideration for gameplay reasons.


A weapon has a DPS rating and a penetration class.

All weapons deal 100% damage to non-armoured enemies but reduced to armoured. This means a high-penetration weapon doesnt always deal high damage to non-armoured foes (in fact would be wasteful agaist such a target).


Idea so far:


---Low penetration (30 % dmg to armoured)





---Normal penetration (55 %...)

Most revolvers

Assault rifles




---Good penetration (75 %...)

Heavy revolvers

Sniper rifles



---Full penetration (100%...)

Fire-based weapons (flamer, molotov etc)


Does this make sense? I also have hitech/energy weapons but i will decide later how these work in my world. Most likely they will fill the roles that conventional weapons didnt fill.


I will NOT have room in my design for different kinds of ammo like shotguns slug, FMJ, hollow-point etc.


Thanks for your input and try to keep it on-topic.


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If I remember correctly, in the real world a bullet proof vest won't stop anything bigger than a 9mm round which is the standard round for semi automatic pistols isn't it? How real do you want this to be? 

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Well as stated i use DPS rating, units have HP and I use a fixed percentage damage reduction for amour. There is also zombies and robots:)


But does my suggestion kinda make sense? I mean how I group the weapon classes into different penetration classes? Its simplified of course but this is just one gameplay system and i dont want to flood the player.


I prefer some kind of:

"Normal guy - I can use my shotgun or pistol. Armoured guy, I should switch to my sniper rifle and spend some rare ammo or he will take ages to take down."


Making weapons have a specific role, so you need to carry different and use them in different situations.

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You could subtract a fixed amount from the DPS when armored and limit the damage to be between 0 and 100.


Base DPS:


Pistol: 100 DMG

Rifle: 150 DMG

Sniper: 200 DMG


Without armor:


Pistol: 100 DMG

Rifle: 100 DMG

Sniper: 100DMG


With armor that subtracts 100DMG:


Pistol: 0 DMG

Rifle: 50 DMG

Sniper: 100 DMG

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with just two types of armor (none or have some), and perhaps a dozen weapon types, a lookup table is probably the way to go, IE the good old fashioned wpn vs AC table concept from classic D&D.


the table should probably show % dmg done, from 100% to 0%, depending on the particular wpn vs armor combo in question.


the trick is setting the percentages in the table to believable values.


a list of the exact weapon and armor types would be required to come up with believable percentages. - along with some knowledge of munitions and armor.


percentages would be better than fixed DP values. that way no base DP value is assumed.  IE a -10dp penalty assumes a 100dp weapon, whereas a -10%dp penalty works with any weapon, irregardless of its base DP.


FYI, to this day, the only weapon that can penetrate any body armor is the arbalest firing a bodkin point bolt


youtube has videos of modern 200lb draw force xbows almost doing it. imagine what a 5000lb draw force xbow would do!





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I dont think thats very intuative for the player. Also strange that pistols would deal no damage whatsoever in your example. I prefer a %-reduction so i can scale many weapons within the same group.




But isnt that what i described in my first post? Or did i misunderstand you. The weapon classes ARE all the weapons. Within them are just quality variations, the weapons function the same way in regards to armour.


For example:


Makarov pistol = 8 dps, (100 % to unarmoured, 30 % to armoured)

HK USP pistol = 12 dps (100 % to unarmoured, 30 % to armoured)


AK assault rifle = 15 dps, (100 % to unarmoured, 55 % to armoured)

SCAR assault rifle = 21 dps, (100 % to unarmoured, 55 % to armoured)



So the weapon CLASS defines what targets are suitable depending on armour, the weapon VARIATION defines dps, range, ammo capacity within that class. Makes sense? Its useful for gameplay purposes.


Do my grouping (of weapon classes) in the first post make some sense? The actual numbers will be tweaked later on obviously.

Edited by suliman

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heavy revolver having better penetration than an assault rifle? most revolvers having the same penetration as assault rifles? Really? I don't think that is true unless you use rifle like pointed bullets in your revolvers...

The more pointed a bullet is, the heavier it is in relation to its caliber (smaller diameter / longer bullet is superior to larger diameter / shorter bullet in this regard), the better its penetration power. The next important thing is muzzle velocity, where the AR bullets are clearly superior to most if not all revolvers (longer barrels). 


Handguns where mostly designed to provide maximum stopping power against unarmoured foes, which makes sense given that they are mostly used in civilian settings (by the police force for example)... penetrative power in this regard is contra-productive, as it lowers stopping power and actually endangers people standing behind the target more than a bullet deisnged to be stopped inside the target.

Rifle bullets on the other hands where developed to give maximum range (in which case a more streamlined bullet is better, hence pointed and as long as possible), and penetrative power (even though body amrour only became practical after WW2, there are other advantages to higher penetrative power in a military setting where you care less about collateral casualities... penetrating the window shields and metal of unarmoured vehicles, or thin walls for example).


The chance to find any kind of handgun today that will compare favourably in terms of penetrative power to even the small caliber NATO ARs is quite low (altough they will beat ARs when it comes to short ranged stopping power, which was the whole purpose of the european 9mm round being developed at the start of the 20th century... it is more complicated than that as AR round have shown MORE stopping power given they hit a bone in the body (which will only be fractured by a 9mm or similar round, with the round being deflected, whereas the AR round turns the bone into shrapnels with an ugly shotgun like effect because of its higher velocity... and there is the ugly tendency of NATO AR round to tumble inside the wound channel. But as for most hits to soft tissue, consider the 9mm round more capable of creating disabling wounds)...


There ARE very new weapons using AR ammunition in a Handgun or SMG body, these are PDWs though (personal defense weapons) and a whole new class of weapon altogether.



If we are talking about body armour, there are basically two classes of body armour (well there are much more, but lets make it simple): Kevlar vests that are good at stopping pistol round up to a certain caliber, but are ineffective against a pointed rifle bullet, and plate armour (which today consists mostly of ceramic plates and is integrated into kevlar vests) which is able to stop even small (NATO AR) to normal (old rifle and AK47) caliber rifle bullets, but most probably is not able to withstand a heavy MG (well, the M2 penetrates up to 30mm of rolled homogenous armour, so don't expect a thin ceramic plate to stop its rounds).


Kevlar vest will stop many bullets as long as they don't strike the same point twice as it is "more elastic", but even a stopped bullet will leave an injury as the impact is not spread over a big area (non-fatal MOST probably, might still degrade combat abilities).


Plate armour will cleanly stop the bullet and spread the impact over a a large area (that of the full plate), thus less risk of injury (which translates to 0% damage inflicted), but the plat has a high risk of cracking in the process, which will lead to a higher risk of a bullet penetrating the plate with each additional impact (thus the plat getting destroyed and 100% damage being inflicted if the additional protection by the Kevlar vest the plate is embedded in does not stop the bullet).


There are much more different types of body armour, for example normal Kevlar vests are not proof against knive stabbings, there are special vests for that (or combined vests)....



Now, translating that into your simplified system without sacrificing too much realism I would go with the following:


Light body armour (just Kevlar): stops all pistol / non-pointed rounds, but about 50% of damage goes through (the damage inflicted by a stopped bullet + the small chance an unarmoured part of the body is hit).

Heavy body armour: stops all round up to light MGs and Rifle caliber, about 25% of damage goes through (modelling the fact that the plates can only cover so much of the armoured area without getting too heavy to wield, the plates getting cracked and destroyed with each hit to them, and of course bullets hitting unarmoured parts).


If you want to, you could give rifle bullets a 50% damage inflicted upon heavy armour whereas pistol rounds only do about 25% (scale the numbers however you like) to represent the kevlar-only parts of the armour actually stopping pistol rounds but being penetrated by rifle bullets.


Then I would restrict the light armour equipped combatants speed and mobility a little to represent the weight and bulk of the armour (police style light armour might be less restricting, military type is), while giving heavy armour wielding combatants more of a malus (about 10% for light and 30% for heavy armour sounds about right IMO)



Now, if you want a weapon to do more damage through the armour (because its penetrative power is just at the threshold to penetrate the armour, or because against kevlar armour or the kevlar armoured parts of heavier armour the caliber of a non-penetrating round actually DOES matter, you could alter the percentages for every weapon class.


I am inconclusive if a bonus system (+5% more damage against light armour), or the damage percentage per weapon instead of per armour is better, I still would keep the two armour types. Because of its construction materials, plate armour models the vehicle armour properties where a round either penetrates and does full damage or bounces of without doin any damage (to the inner parts of the vehicle or the combatant itself, the armour might still crack) more than kevlar armour does (which will just prevent the bullet from penetrating, but heavier rounds will still inflict heavier indirect damage).


Keeping 2 values models that perfectly.


lets make 4 examples:


automatic pistol / normal revolver: 40%  /20%    (light/heavy armour damage)

Magnum Revolver:                         75% /30%     (The Magnum rounds might be stopped by Kevlar armour, the energy they contain will still be enough to knock out an opponent)

Assault Rifle:                                  100%/50%

Sniper Rifle                                     100%/90%   (special in this case, as the shooter can bypass the armour by aiming at unarmoured parts)

Edited by Gian-Reto

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Thanks for the info Gian. There is no room in my game for two different kind of amours though... That would be neat for a more tactical game with focus on military/police units (as stated I have zombies and robots as well to deal with and many other gameplay systems the player has to deal with).


The reason why revolvers have so good armour penetration is somewhat gamey. I need something low-range, that are not to good in general (such as AR will be in my game) to fill that role. Also, this is almost a gaming standard, just look at the revolver in halflive/halflife 2 (they even overdid it in that game but it DID work for that gameworld).


What about fire being very armour penetrative? Seems logical right?

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You said you're doing simplistic, but giving 4 ranks of armor penetration isn't very simplistic. 


It would be better to break it down into 1 or 2 categories. Either give weapons the stat [Armor Penetrating] or not. Failing that: 3 categories. Low, Medium, High.


Since you can't know until the balancing phase whether a specific mechanic will work as expected, simplicity will make it easier down the road. I'd give weapons 25% pen or 75% pen and leave it at that. Later down the road it will make it easier to deal with weapon balance because you can tweak the Rate-of-fire and Damage in isolation. If at that point, 25% and 75% pen doesn't work like you think it should, then add a 3rd Penetration level.


There will be so many other variables that you can bounce around, that it's needlessly complicated to use 4 variables when you could have 2.


The fact that you're doing only Armored vs Non-Armored is a good idea too. That will simplify gameplay and make balancing easier too.

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Yeah, i think with only two categories of enemies, i'd start as Weeble suggests, and just go with armor penetrating and not armor penetrating damage.  I would definitely not reduce any damage to zero, because it is not fun getting stuck with weapons that all do zero damage, maybe just start with half damage if the gun doesn't have the right stat.  (If you wanted to punish usage of penetrating vs unarmoured)  Or double damage if the gun has the right stat -- which is the same thing, but tends to make the player feel better about using the right gun, than if the player uses the wrong gun.  I know, silly psychology trickery.

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