In modern warfare 2 stopping power pro or hardline?

I need heeeeellllpppp. I'm pretty good with some guns like UMP acog and m4a1 stopping power but I've been epicly troubled. stopping power pro or hardline for m16 or m4a1 or should I put one man army on a class with stopping power and switch to a class with hardline on so I can get my FRICKIN AC130 for 10 kills when I have 9 kills pllllzzzz heeeelllllpppp