User blog comment:Heatedpete/Most Hated Gun on any CoD so far/@comment-3144996-20100313224105

The UMP .45 fires .45 ACP, not 9mm, hence the name. But yes, the UMP40 as I call it is too powerful at range for an SMG (but does have a bit of recoil)

For me it's the ACR. It might not be very powerful but when someone starts getting me hit with it while I'm sniping, the aim just goes off to hell.