Ballista, I prefer the looks mainly. If I'm on Softcore DSR though.

Oh me too in CoD4 with an Acog

How do I snipe?

Dsr > if still learning

Balista > for good players
(Just quickscope vertical and those hitmarkers will be gone.)

use a smg

pdw is the #1 sniper rifle in the game

Vouch sniping is ezmode with it nahwhatimean

Lol acog

Acog on the M40A3 is lethal on cod4.

In my opinion, if you want to quickscope, you have to quickscope to get better at it. ( hardscoping won't make you better )
Just practice on the cpu bots the game has to offer.
Also start right on 14 sensitivity and get use to it, switching it will throw you off; and you would have to get use to it again.
Both the snipers that one hit kill in the chest seemed great to me, haven't played the game alot so can't offer too much on that.
Again, this is just my opinion; so anyway, goodluck.