The K7 with extended clips is just absolutely fucking amazing. The fire rate is matchable only by the Uzi, and it is actually pretty accurate, the only downside is it takes some decent aim to do well with it because it DOES take quite a few shots to kill someone with it.
The UMP is another amazing weapon. I have found the UMP to be even more powerful than some of the assault rifles. I dont trust the stat bars that nexon shows me, because that UMP is beastly. Its low recoil, power, and decent fire rate make it an all around gun for short to medium range.