The quality way would be to google search a pallet carousel. It's a little pricey, but it's durable and will last. It's two pieces of angle rolled into rings with bearing rollers in between.Bolt one to your frame, one to your turret. Only thing from there is balancing.
I didn't have the money for a carousel, so I opted to buy 1" work rollers from a woodworking supply shop. I cut my hole in my shell, lined the circumfrence with the rollers and put my turret on top of that. I did have to adjust my design to allow for the ring that holds the turrent ring over top of the rollers. That sucked. If and when I do it over, it's getting a carousel.
Kent Island Sea Monkeys - Semper Gumby
PAINTBALL ADVENTURE PARK