Most overpowered: SCAR-H, UMP.45, RPD, SPAS-12, PP-2000/M93R's/ .44 Magnum, Barret .50 Cal, for each of their classes respectively.
RPD 2 hit kills at all ranges with stopping power, it does 50 damage, the same damage as a suppressed sniper rifle without stopping power. It has the most controllable recoil for all machine guns, the L86 LSW has the same damage but a very high rate of fire making it one of the most deadly weapons in the game if used effectively. Stupid CoD kids don't dive this far into guns, though, so you might OMFG BBQ at what I'm saying.
none of the guns are overpowered. in real life one shot kills you not 4 or 5 so to say guns are overpowered is a lie, they are really underpowered
True. In real life, a single bullet should kill. Hence, hardcore team death match is available, if you want to play realistically.
But when people say overpowered, they mean how strong the overpowered gun is compared to another in terms of MW2.
Favorite sniper rifle? M21 EBR. My favorite shotgun is akimbo rangers (they are beasts when combined with stopping power and steady aim). My favorite handgun- I think, might be the .44 Magnum. I love the M93 Raffica (especially on akimbo), and, my most favorite, UMP45 (you can akimbo them, but I don't want to).