If you are level 35 and under, then I may have some advice.
If you are a...
A) Person that recklessly runs out and starts putting lead into people, then I recommend using Akimbo P90's with rapidfire. Bullets fly EVERYWHERE! Just try not to die, because that is a dangerous weapon! Also have your secondary as Akimbo PP2000 with Extend Mags. Also have Sleight of hand perk on! And you HAVE to equip the Bling Pro perk!
B) A person that uses their brain rather than stomping out into the middle of battle with an AA12, then A SCAR-H Undermount-Shotgun with ACOG scope is right for you! Take your time to hide behind a crate for a bit. Remember, you need to have the Bling perk attached.
C) A Sniper, Then Use the Barrette 50.cal with Thermal attached. USE THE COLD-BLOODED PERK SO PAVE LOWS AND SUCH DO NOT PUT A GIANT HOLE IN YOU! Get in a shady place with some cover, get prone so you have better accuracy. For your own safety, do not use a sniper while playing on Rust, you WILL get torn to shreds...
I hope this helped a little bit at least....
There's a flaw with some of that logic: A.) you cant use Sleight of Hand and Bling at the same time, but at least you use the P90 rather than the UMP45(<-- I hate this gun lol) but the advice is good
I know. I noticed that today.
Thanks for advise man, it is nice advise and me too using SCAR.
if you can, when first prestiging (lvls 5-10) keep using the default classes and getting as many kills as you can with them to unlock additional attachments (eg: acoge on barrett)
modernwarfare 2 is like one game that is hard to get xp on so you need a ton of kills!!!