In reality range and accuracy are related. In call of duty the further range means lower damage. The weapons have a maximum damage at close range and a minimum damage at far range. Lots of people who take the game seriously use Den Kirson's weapon guides. He goes in to the games code to examine how they work. Check his stuff out here. http://denkirson.xanga.com/735016527/black-ops/
First off, don't believe anything you see on the in game stats. They are wrong, they have been wrong in all of the previous games and more than likely they will always be wrong.
You bullet will always go straight if you are aiming down the sight. Each gun has a "sight in period", usually around .2 of a second for SMG's and .25 for AR's. During this time, it's basically like shooting from the hip, but to a lesser extent. Once you are sighted in, the bullet will hit where the tip of your front sight is.
Range is a bit misleading (again, I'm not referring to the in game stats). You bullets don't disappear after a certain range (except for shotguns). They will travel forever. Each gun has a max and min damage. Take for example, the Famas does 35 damage up to 37 meters. Once the bullet travels past 37 meters, it loses damage, until it reaches 25 damage at 50 meters.
All the stats are wrong. I don't think they have been right on any CoD game so far.... But Yes, the silencer reduces damage on snipers, at the least. Can one shot people in the chest with the L96 sniper rifle, but when I put on the silencer, takes 2-3 shots even in the head for some dumb reason.... man... It really sucks. I liked sniping in Fallout:New Vegas with my silenced sniper rifle.... Could take out a group of 4+ people before they even noticed BadGuy A was missing his head. Hahahaha. Oh well... Maybe some day they will make a game where things make sense. Waiting on the day they come out with a game where people don't die from paper cuts!
The extraordinary number of uninformed people in this thread bugs me to no end.
The silencer does indeed reduce range on all guns except sniper rifles. On sniper rifles, you CAN NOT get a 1-shot kill if you're using a suppressor unless the enemy is already wounded. Yes, sniping has been extremely gimped, Yes, it's stupid.
On any other gun, let's go with the M14 since it's been used already. Now as everyone has said, the M14 is a 50-40 weapon. Very high damage. The damage drop-off on the M14 begins at 32.5 meters away from you. So if a guy is 32.5 meters away, it will still be a 2 shot kill, but one millimeter beyond and it will be a 3-shot.
If you add a suppressor to the M14, this damage drop-off begins at 15 meters rather than 32.5 meters, reducing the effective 2-shot kill range of the M14.
http://www.denkirson.xanga.com . Try it to see other gun stats and so that you can no longer be the uninformed one in the thread.
Suppressors lower damage at range. So if your shooting long range, the damage is decreased on any gun. Considering your using a sniper rifle, you are probably using it for long range shooting, therefore the damage is decreased.
When the range bar decreases, it means damage at a further ranges is decreased.