Only put about an hour into and I could use some guidance with weapons selection.
 
I'm only level 4 and only have about 450 points right now and I want to save up to get the Medical thinger. Anyone have any suggestions for Assault Rifles to use? And a good game mode to get points? I'm finding it difficult to rack them up, probably cause I'm not very good right now.

Well, the easiest way to rank up is to play the "directives" mode (its not really a mode but it puts you into a random game that needs players). Directives gives you a fat xp bonus even if your team loses. As far as weapons go, if you like assault rifles, make sure you save up for the tier 2 AR (don't waste your time with the tier 3). However, my recommendation would be to grab and improve the LMG from your faction (the free DLC for your faction includes a slightly improved tier 1 LMG). The bipod is great on defense as you can prone near a door and rack up kills as people try to enter buildings. I'm assuming you went S.V.E.R, in which case they have the most powerful but least accurate guns, making the foregrip a reasonable choice for their guns.

The DLC weapons will show up in your loadout screen (it'll have the same name as the tier 1 but with a slightly different designation and higher stats). I liked using the LMG over the assault rifle, but your mileage may vary there.