Firearms: Grouping is to the right (lefty shooter)?

I was out shooting and something's been bothering me. At 25 yards, my grouping is pretty tight but it's a little to the right of what I'm aiming at. I'm a left handed shooter with a .40 handgun. I've read that this *could* be because I don't have enough finger on the trigger, but I adjusted and still have the problem. Could this be anything else? I'm absolutely NOT anticipating the recoil. Thanks for the help.