Half Life 2 Damage Model

I was playing with the Half Life 2 SDK again (as well as the Hammer editor) though I haven't really got anywhere with it as I'm still trying to work out how to actually change the weapon damage variables. I did play around with the velocity and mass of bullets though was disapointed to find that this doesn't actually increase the damage of a round rather the damage done by a weapon in the engine is not related to these factors (though it's makes a lot of sense to scale accordingly). I now have a pistol that can knock objects miles. Hopefully I'll figure out the whole damage model thing soon, I thought I was on to a winner with CVar as it is a assigned for all weapons but it really is just registering a console variable.