Minigun powerup only repeating once?

So I have powerups in my game but for some reason the minigun isn't working. I want it to shoot rapidly for 5 seconds. I'm not sure what I'm doing wrong here. It only shoots one bullet.

Also how do I make the RocketPropulsion go in a straight line from the minigun? I tried specifying the rocketpropulsion without a target but it just goes to the center of the baseplate.

function Minigun()
	repeat
		local rocket = Instance.new("Part", script.Parent.Physical)
		local propthing = Instance.new("RocketPropulsion",rocket)
		local rocketscript = script.Parent.Physical.RocketScript:Clone()
		local offset = 10
		local fire = Instance.new("Fire")
		rocket.Position = script.Parent.Parent.Position + script.Parent.Parent.CFrame.LookVector*offset + Vector3.new(0,10,0)
		rocket.Size = Vector3.new(1, 1, 4)
		rocketscript.Parent = rocket
		rocketscript.Disabled = false
		rocket.BrickColor = BrickColor.Random()
		fire.Parent = rocketscript
		propthing.CartoonFactor = 1
		propthing.MaxSpeed = 1000
		propthing:Fire()
		warn("Incoming rocket from the Big Rig!")
	until wait(5)
end