[quote name='The 7th Number']Rocket turret? Where is that located?[/QUOTE]
When you spawn, it's straight ahead of you, ground level. To the left of the lake. You drive straight ahead with the lake to your right. I'd say stop about 300 feet. You would to be somewhat covered by the rock formation, and to be a good distance from the groups spawning. It takes some fine tuning, but when you do it, you can kill the grunts with ease, work on your vehicular commendation, and usually get perfections (or whatever the commendation is for not dying in FF). Don't be afraid to hop out of the turret if things get hot with a fuel rod, etc. Also, I'll hop out and clean up a few of the grunts that are walking around if they're not doing downhill.
It's a pretty effective way to do G-Poc, IMO, and it seems like it's more fun.