Hit Points

Hit points are the "points" of damage you can take in Halo 3. In multiplayer, players have 45 "health" hit points, and 70 "shield" hit points. Shield hit points recharge at a steady rate that has not been given an exact numeric value; Health hit points, however, recharge at a rate of 9 points per second after 10 seconds of "wait time", just like the wait time for shields to start recharging.

Damage Values
Several weapons have been given specific values of damage that they do in hit points. -The Battle Rifle does 6 points of damage per shot that hits out of it's burst, for a presumed total          of 18 points of damage per burst.

-The Assault Rifle does 7.5 points of damage per shot that hits.

-Most weapons have melee attack damages of 70. Brute weapons, however, do 72 damage with melee attacks.

It can be assumed that plasma weapons deal significantly more damage to shields per shot than to health per shot, which means that the values of damage done to shields vs. the values of damage done to health may differ by weapon. However, it has never been explicitly stated that this applies to any weapons but plasma weapons.