Need help with projectile

My problem is, I don’t want my projectile to be dragged by gravity gun.
I tried doing this: http://wiki.garrysmod.com/page/PhysObj/EnableDrag But this only stop it from being dragged by the physgun that comes with GMod, not the gravity gun from HL2. Anyone one know how to fix this? Thank you.

Use these hooks:
GravGunOnDropped
GravGunOnPickedUp
GravGunPickupAllowed
GravGunPunt

Same goes for physgun.

Alright thanks.