I plan on modding the pistol so its a full-on sniper rifle, which kills people in one hit, but how do I increase the damage done by a bullet?

In a nutshell: Sharpness does it.

Or Mass or ParticleCount or FireVelocity.

Not necessarily, sharpness, firevelocity, and the mass of the bullet are all factors.

Of the three I've seen sharpness as the biggest in altering the damage done, though. I s'pose it depends on the weapon though.

Ah okay thanks!

Oh just another quick question, where can I edit the pistols ammo? Ammo.ini shows everything but the pistol.

It's in the magazine.

I'm just modding the pistol so it looks like a sniper rifle and does extreme damage, but there's no sharpness anywhere for the pistol. SharpLength = # is the closest thing I could find.

Sharpness is in the round code, RoundCount is in the magazine code.

Oh wait I've got it. The pistol shares the same ammo as the SMG... kinda weird

Actually, pretty logical, as SMGs tend to fire pistol rounds.
You can define a new round type, link that in the pistol magazine code, et voila, your
pistol no longer fires the same rounds as the SMG.

copy the round code,
change the name,
change the sharpness/mass/whatever,
change the linked ammo type in the pistol mag

VERY IMPORTANT READ THIS

Okay, all of you are right... sort of. Mass, Velocity, and Sharpness work together to determine how much a projectile penetrates. But the damage itself is a somewhat different story.

See, if a projectile is too weak, it won't penetrate. If it's strong enough, it'll make an entry wound. If its really strong, it will make an entry AND an exit wound.

The importance of this is the fact that the wounds themselves are what determine the damage. You'll notice that actors and parts of actors have different entry and exit wounds set. Well, if you check out the Wounds.ini file in Base.rte/Effects/Wounds, you'll find specifications for different wounds. You'll see that they have some variables, including BurstDamage. THAT is the stat that determines how much damage an actor takes when they get that wound.

So, in a nutshell, the maximum damage an actor can take is the sum of their EntryWound and ExitWound BurstDamage values.

... at least normally. Something else to consider is that headshots multiply the BurstDamage value by 5. Still, even with all that combined, a gunshot wound that passes all the way through the head typically isn't fatal in this game, unless you set it to be that way yourself.

You may be a bit perturbed with this, but consider this: the clones in this game don't actually have their own brains. They're just husks being controlled by your brain remotely. So whatever is in their head, though vulnerable, isn't quite as destructible as you would expect.

On a final note, though: remember that every actor and device in the game has a GibWoundLimit. This is the number of wounds something can take before it explodes. So, you could try the trick of having a gun fire more than one bullet with absolutely no spread between them. Not only would each bullet cause damage separately - making more wounds - but also if theres enough it might just gib something instantly.

...hopefully all that wasn't too much to take in.

@Darlos: There's also the solid projectile route; use massive projectiles to trigger the GIL.

Make it a really close-together-spread shotgun blast. Gibs every time.