You should have specified that.
And, for a gun:
datablock ProjectileData(YourgunProjectile)
{
projectileShapeName = "./YourBullet.dts";
directDamage = 30;
directDamageType = $DamageType::YourGun;
radiusDamageType = $DamageType::YourGun;
brickExplosionRadius = 0;
brickExplosionImpact = true; //destroy a brick if we hit it directly?
brickExplosionForce = 10;
brickExplosionMaxVolume = 1; //max volume of bricks that we can destroy
brickExplosionMaxVolumeFloating = 2; //max volume of bricks that we can destroy if they aren't connected to the ground
impactImpulse = 400;
verticalImpulse = 400;
explosion = gunExplosion;
particleEmitter = ""; //bulletTrailEmitter;
muzzleVelocity = 90;
velInheritFactor = 1;
armingDelay = 00;
lifetime = 4000;
fadeDelay = 3500;
bounceElasticity = 0.5;
bounceFriction = 0.20;
isBallistic = false;
gravityMod = 0.0;
hasLight = false;
lightRadius = 3.0;
lightColor = "0 0 0.5";
uiName = "YourGun Bullet";
};
Isolated is the damage it does, per shot.