It's an unanchored cannon that is held together by welds. There is a weld called Swivel in the joint that connects the joint to the barrel.

What I've tried:

script.Parent.Joint.Swivel.C0 = script.Parent.Joint.Swivel.C0 * CFrame.fromEulerAnglesYXZ(0,0,-0.1)

The problem is that if the cannon is facing one way, the barrel rotates up, and if it's facing the other way it rotates down.

So how do I make it rotate up no matter what direction it's facing?

Thanks.