It's a common spot to fire at. You see the door open, aim at the middle of the top 6 on the red box to the left, the aim a little right and line up on the silver. Once you see movement, fire... or as I do, just tap fire every second or so. Gets em every time. Much easier with a scout.
If that's hackin', I'm sorry. Oh well, like I said, hard to prove you're not hackin once accused.