Making a cannon, How can I have the cannonball shoot in the direction of the cannon?

partstore = game.ServerStorage.CannonBall
workspace.Launch.CanCollide = false
pressed = false
turningangle = workspace.Launch.Orientation
function shoot()
if pressed == false then
local storepart = partstore:Clone()
storepart.Parent = workspace
storepart.Position = workspace.Launch.Position
storepart.Orientation = workspace.Launch.Orientation
storepart.Velocity = Vector3.new(-200,0,0)
pressed = true
wait(5)
workspace.CannonBall:Destroy()
pressed = false
end
end

game.Workspace.Launch.ClickDetector.MouseClick:connect(shoot)

I know the script is really messy right now but I'm planning to tidy it once the basic functionality is sorted.
I'm trying to get the storepart.velocity to shoot in the direction the cannon is pointed at around 200 studs, I know how to get it to shoot at a specific angle, but I don't know how to get it to shoot in the constantly changing rotational direction of the cannon.

If I were you I would try CFrame, because if you connect them with CFrame, the StorePart's Rotation will be the same as the Launch rotation.