Code:
AddGib = Gib
GibParticle = MOPixel
CopyOf = Grenade Fragment Gray
Count = 40
Spread = 360
MaxVelocity = 30
MinVelocity = 15
AddGib = Gib
GibParticle = MOPixel
CopyOf = Grenade Fragment Yellow
Count = 50
Spread = 360
MaxVelocity = 40
MinVelocity = 20
In these ones, change the Min/Max velocity to make them go faster (so they go farther in the time they live), or you'd have to change the lifetime of the actual particle, which is in a different .ini. You can also up the count to make more particles, and therefore more chance of damage.
The way these kinds of bullets work is that they explode and "gib" stuff when they die. These bullets have a GibImpulseLimit of 10, so they're relatively easy to destroy, and then they do die, everything that has an "AddGib" before it will come out of the bullet with those settings (count/spread/velocity).