Unlike Call of Duty: Modern Warfare 2, you won't be getting the pro version of a perk by completing a challenge. In Call of Duty: Black Ops you need to complete a set of 3 challenges in order to get...
When you finish the challenge "Lightweight Pro IV" under the "Perks" section, the perk Lightweight upgrades to Lightweight Pro. Lightweight Pro allows the player to raise their weapon more quickly...
Hmm... I mostly use stopping power pro because I believe that it helps alot. But I do have one or two classes that has on lightweight pro. Lightweight pro is also good because you can aim in faster...