The gun that I should focus?

I got most of the m4 and ak, and few days ago I have won the m14. I tried it in a few games and found while the power is good, when I spray I tend to kill longer than I spray with aug or m4...so i am wondering if i should adjust to m14 or just use it as a more powerful wall bang gun. I use aug camo in snd and I think its the best gun for me now, around 50%hs in snd. But the power sometimes let me down and the box shots takes forecer to kill. Please comment whether you think i should switch to m14 or stay with aug/m4. Thx