im level 13 and am looking forward to using the feline, but i need a weapon unlock to use it, how do you get them? or is it just to do with rank, im sick to death of using the bloody scar thanks

I'm level 7 and I already got like 3 weapon unlocks. Maybe a bug? Also, you need to be a certain level to unlock more advanced guns. If you hover over them you will see which level you need to be in order to be allowed to unlock it.