Why wont this gun script work?

Player = game.Workspace.LocalPlayer																																								
Gun = script.Parent																																						
Ammo = 5																																							
mouse = Player:GetMouse()																																					
function Shoot()																																			
	if Ammo > 0 then																																
		Bullet = Instance.new("Part",  Workspace)																												
		game.Debris:addItem(Bullet, 10)																																																														
		Bullet.Shape = "Ball"																												
		Bullet.Size = Vector3.new(0.2,0.2,0.2)																													
		Bullet.TopSurface = "Smooth"																																																										
		Bullet.BottomSurface = "Smooth"																																																
		Bullet.BrickColor = BrickColor.new("Dark stone grey")																																			
		Bullet.CanCollide = false																																
		Bullet.CFrame = Gun.Handle.CFrame																												
		Bullet.CFrame = CFrame.new(Bullet.Position,mouse.Hit.p)																												
		v = Instance.new("BodyVelocity", Bullet)																										
		v.velocity = Bullet.CFrame.lookVector *90																											
		v.maxForce = Vector3.new(math.huge, math.huge, math.huge)																											
	end																																											
end																																													
																																						
Gun.Activated:connect(Shoot)

Well, you're skipping a line whlie setting the variable.. why?

Also, your direction may be off.

If this doesn't work then you're doing something wrong outside of the script.

local Player = game.Workspace.LocalPlayer
local Gun = script.Parent
local Ammo = 5
local mouse = Player:GetMouse()

Gun.Activated:connect(function()
	if Ammo > 0 then
		Bullet = Instance.new("Part",  Workspace)
		game.Debris:addItem(Bullet, 10)
		Bullet.Shape = "Ball"
		Bullet.Size = Vector3.new(0.2,0.2,0.2)
		Bullet.TopSurface = "Smooth"
		Bullet.BottomSurface = "Smooth"
		Bullet.BrickColor = BrickColor.new("Dark stone grey")
		Bullet.CanCollide = false
		Bullet.CFrame = Gun.Handle.CFrame
		Bullet.CFrame = CFrame.new(Bullet.Position,mouse.Hit.p)
		v = Instance.new("BodyVelocity", Bullet)
		v.velocity = Bullet.CFrame.lookVector * 90
		v.maxForce = Vector3.new(math.huge, math.huge, math.huge)
	end
end)