Hi all, any help or advice on solving this would be much appreciated.

I've not been playing long, not just BO, but FPS, so maybe i'm doing something wrong. I'm trying to take out a Sentry Gun for Ghost Pro, but everytime i take one out it doesn't register as a Sentry Gun kill, it comes up as "Took Out Turret". I've tried taking out opponents SG's and giving away my own to take them out but it makes no difference. I've taken out well over 10 and can upload an example if that helps at all.

Am i doing something wrong?

TIA.