Fenr1r

I'm looking for a 3x,4x or 5x or anything in between optic for my rifle. I like the PK-A from Battlefield 3 http://battlefield.wikia.com/wiki/PK-A but from what I have seen the real PK-A is only a 1x optic. So what are my choices? The absolute max I am willing to spend is 500 but would like to keep it under that. I prefer something with a red dot but am willing to get a traditional optic.