What gun should I get at Seargent?

Well, here are some little desriptions to some guns I suggest, hope it helps:

M4

Good gun, good accuracy and relative lightness in exchange for weakier power and average results at very close range. Recoil is pretty much controllable, and it's a good allaround gun. The bad thing in it that it won't be an all good gun for a rusher in TD (Closerange on it isn't what you exactly expect at sargeant level).

SG552

Highly defencive gun. It's prescision and power are all good, but you don't want to run around a lot while shooting it, recoil isn't one of easiest. Besides, it's heavy, so you won't rush much with this one. A lot of new players are getting this gun without knowing how actually use it, so it's a bit hated by some.

Scar Heavy:

A somewhat substitute for AK. It is easier to control at bursts due to previsible and easier to handle recoil than the AK, but it's also heavier than one. It's reload time isn't great, but it's power paysback for it, I think it's almost same damage as AK-47's, if not exactly same.

MP5

Your basic smg, good recoil control, fast ROF and Reload Rate. Light to run with (same weigh as a Deagle), and deadly prescice at short to medium range. Won't help much below there, it's an SMG. A good choice if you play TD or GM, in close range this one is decent.

Besides, don't count too much on BM guns. I got two deagle camos in 50K gp, but this was pure luck cause now I suffer to get the MSG90 and AUG-C (Wasted 700K GP +)

The XM8-Adv is no better than the XM8 regular. The triple shot function on the scope kills it.