how do i set my distance on my ray casting gun?

heres my script

game.Players.PlayerAdded:Connect(function(p)
	mouse = p:GetMouse()
	distance = 15
	mouse.Button1Down:Connect(function()
		ray = Ray.new(mouse.hit.p,(mouse.hit.p - p.Character.UpperTorso.CFrame.p).unit * 2)
		hit,pos = workspace:FindPartOnRay(ray,p.Character,false,true)
		
		line = Instance.new("Part",workspace)
		line.BrickColor = BrickColor.new("Really red")
		line.Anchored = true
		line.CanCollide = false
		line.Transparency = 0.3
		line.Name = "Line"
		local dir = (p.Character.UpperTorso.CFrame.p - pos).Magnitude
		line.Size = Vector3.new(0.3,0.3,dir)
		line.CFrame = CFrame.new(p.Character.UpperTorso.CFrame.p,pos) * CFrame.new(0,0,-dir/2)
		print("done")
	end)
	
end)

i really dont know what im doing wrong lol

ps: the part where it says like .unit * 2 doesent work i use to but not any more

The issue is in line 5. The ray starts at the hit position instead of whatever it's supposed to come out of.