Ok, I have a "bandage applicator" and a "bandage." The bandage applicator is a gun that uses bandages for ammunition. The bandage applicator is:

Name Bandage Applicator
ShortName kfbandageapp
Ammo kfbandage
Icon kfbandageapp
Colour 255 255 255
ItemID 26386
ReloadTime 90
Recoil 0
Damage -15
Accuracy 0
ShootDelay 0
ShootSound kfbandageapp
ReloadSound kfbandagereload
Mode FullAuto
Scope None
ZoomLevel 1.5
DistortSound False
Deployable False
DeployedModel None
BulletSpeed 50

And the bandage is:

Name Bandage
ShortName kfbandage
Model Bullet
Colour 255 255 255
ItemID 26387
Icon kfbandage
FallSpeed 0
RoundsPerItem 1
Damage 1
Explosion 0
ExplodeOnImpact True
Fuse 2
FlakParticles 0
Fire 0
BreaksGlass False
HitBoxSize 0.1
HitSound kfhit
Penetrates False
SmokeTrail False

ShapelessRecipe kfbandage2
RecipeOutput 4

MaxStackSize 16

When I use it on a mob, it just acts as if it were hurt, but its health stays the same (I wounded it beforehand). Should I be able to set damage values to a negative number?

By the way, potions are lame. :P They don't feel authentic. (with packs like mine) Not that Minecraft is a realistic AAA million dollar budget (ok, sort of) game.

I'm not very familiar with variable types, but if the damage value is set to a whole number, can't someone on the team set the damage variable to an integer? Or does Minecraft not work that way?

So...you want to use a gun for healing? seems a little odd.
I'll look into getting this to work tomorrow.

bandage applicator
bandages

I guess if you want to call a bandage applicator a gun, then yes. There's not much else that heals players anyways. Other than potions. Which I don't want to use. Here are the textures in case you're interested:

And here's the bandage application sound: https://dl.dropboxusercontent.com/u/37933167/MC1.5%20Content%20Packs/kfbandagereload.ogg
I used sounds from Firearms: Source, by the way. I'm not quite a sound engineer. :)

"tomorrow"
DON'T LIE TO ME
</3

nah, I'm just kidding. Bandages aren't of utmost importance right now anyway. I still need to get Vunsunta's permission for his sounds before I release the pack (I'm still not done, too).

Ah yeh, definitely forgot about this :S

When you load up the file gun file with the negative damage, does it say that it fails to load?

The log does not say anything about the bandage or bandage applicator. The only bad stuff is about the classes (though they work fine...) and the missing kfg3a3ammo2 texture, which is my fault.

2013-05-28 17:45:39 [INFO] [STDOUT] Flan's Mod : Loading Flan's mod.
2013-05-28 17:45:39 [INFO] [STDOUT] Flan's Mod : Loaded content pack : Battlefield 3 Pack 3
2013-05-28 17:45:39 [INFO] [STDOUT] Flan's Mod : Loaded content pack : Eastern Front Japanese Expansion Pack
2013-05-28 17:45:39 [INFO] [STDOUT] Flan's Mod : Loaded content pack : Eastern Front Pack
2013-05-28 17:45:39 [INFO] [STDOUT] Flan's Mod : Loaded content pack : European Theatre Pack
2013-05-28 17:45:39 [INFO] [STDOUT] Flan's Mod : Loaded content pack : Firearms Source Pack
2013-05-28 17:45:39 [INFO] [STDOUT] Flan's Mod : Loaded content pack : Parts Pack
2013-05-28 17:45:39 [INFO] [STDOUT] Flan's Mod : Loaded content pack : Somme Offensive Pack
2013-05-28 17:45:39 [INFO] [STDOUT] Flan's Mod : Loaded content pack : Vietnam War Pack
2013-05-28 17:45:39 [INFO] [STDOUT] Flan's Mod : Loaded content pack : Zombie Survival Pack
2013-05-28 17:45:39 [INFO] [STDOUT] Flan's Mod : Loaded textures and models.
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Loaded bullets.
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Loaded guns.
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Loaded parts.
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Loaded planes.
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Loaded vehicles.
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Loaded AA guns.
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Loaded gun boxes.
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Loaded armour.
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add km1911a1 to player class kefusaantitank but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add km1911a1ammo to player class kefusaantitank but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add kthompson to player class kefusaassault but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add km1911a1 to player class kefusaassault but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add kthompsonammo to player class kefusaassault but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add km1911a1ammo to player class kefusaassault but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add kbar to player class kefusaeliteassault but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add km1911a1 to player class kefusaeliteassault but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add kbarammo to player class kefusaeliteassault but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add km1911a1ammo to player class kefusaeliteassault but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add km1garandbayonet to player class kefusaeliterifleman but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add km1garandammo to player class kefusaeliterifleman but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add km1919 to player class kefusamachinegunner but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add km1911a1 to player class kefusamachinegunner but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add km1919ammo to player class kefusamachinegunner but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add km1911a1ammo to player class kefusamachinegunner but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add km1903a4 to player class kefusamarksman but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add km1911a1 to player class kefusamarksman but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add k3006ind to player class kefusamarksman but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add k3006ind to player class kefusamarksman but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add k3006ind to player class kefusamarksman but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add k3006ind to player class kefusamarksman but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add km1911a1ammo to player class kefusamarksman but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add km1903a3bayonet to player class kefusarifleman but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add k3006ind to player class kefusarifleman but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add k3006ind to player class kefusarifleman but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add k3006ind to player class kefusarifleman but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Tried to add k3006ind to player class kefusarifleman but the item did not exist
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Loaded player classes.
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Loaded teams.
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Loaded recipes.
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Loading Flan's mod.
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Loaded properties.
2013-05-28 17:45:40 [INFO] [STDOUT] Flan's Mod : Loading complete.
2013-05-28 17:45:42 [INFO] [STDOUT] [Flan] Hooking complete.

Closing this now that medi kits exist.