I'm gonna start off and assume a lot of people don't actually know this but the in-game weapon stats are false. Sniper Rifles are a good example. In MWR (CoD4), W@W, and MW2, every sniper rifle does the same damage of 70 (every player has 100 health). Stopping power adds 40% more damage so the damage goes to 98. To kill someone in one shot with a sniper you have to aim for certain areas where you get "hit multipliers". For example, you shoot someone in the head(or neck) it does an additional 50% more damage, if you shoot them in the chest or torso(depending on the gun) it will do 10% more damage. If you shoot someone in the legs you won't do any extra damage.

Check this site out for the real weapons stats of each gun and weapon.
Call of Duty 4 | DenKirson on Xanga
in the upper left hand corner you can select what game you want to look at, Black Ops isn't out yet the author doesn't have any data on it yet