My gun script is not working at all. It sends bullets flying in the wrong direction??

My gun script goal is to send a bullet flying at a target but when I play it in-game not in studio the bullets fly in the wrong direction. Can anyone fix the code of this? Thanks in advanced!

originalAmmo = script.Parent.Configure.Ammo.Value

function computeDirection(vec)
	local lenSquared = vec.magnitude^2
	local invSqrt = 1 / math.sqrt(lenSquared)
	return Vector3.new(vec.x * invSqrt, vec.y * invSqrt, vec.z * invSqrt)
end

local isActive = false
local canfire=true
local playerName

function fire(v)
	if canfire==true then
		script.Parent.Handle.Fire2:Play()
		script.Parent.Handle.Fire:Play()
		script.Parent.Configure.Ammo.Value = script.Parent.Configure.Ammo.Value - 1
		local dir = v - script.Parent["Handle"].Position
		dir = computeDirection(dir)
		local pos = script.Parent["Handle"].Position + (dir * 8)
		local p = Instance.new("Part")
		p.Shape = "Cylinder"
		p.Anchored = true
		p.Name = "Projectile"
		p.Material = "Neon"
		p.Color = Color3.new(255,255,255)
		p.BrickColor = BrickColor.new("Institutional white")
		p.Size = Vector3.new(.5, 2, .5)
		p.Orientation = dir
		p.CanCollide = false
		local s = script.Parent["ProjectileScript"]:Clone()
		s.Disabled = false
		s.Parent = p
		p.Parent = game.Workspace
		s.Value.Value = script.Parent.Configure.Damage.Value
		s.Headshot.Value = script.Parent.Configure.HeadshotDamage.Value
		p.Parent = workspace
		p.Anchored = false
		p.Position =script.Parent.Flash.Position
		p.Velocity = (playerName.Character.Head.Position - v).unit * -400 + Vector3.new(math.random(-2,2),math.random(-2,2),math.random(-2,2))
		local upforce = Instance.new("BodyForce")
		upforce.Parent = p
		upforce.force = Vector3.new(0, p:GetMass() * script.Parent.Configure.Speed.Value , 0)
		script.Parent.Flash.Light.Light.Visible = true
		wait(0.05)
		script.Parent.Flash.Light.Light.Visible = false
		wait(script.Parent.Configure.ClickTick.Value - 0.05)
		canfire=true
	
	end
end


local canrel = true
local canAuto = true

if script.Parent.Configure.Auto.Value~=true then
	script.Parent.Activated:Connect(function()
		if script.Parent.Enabled == true then
			if script.Parent.Configure.Ammo.Value > 0 or script.Parent.Configure.InfiniteMagSize then
				fire(playerName.Character.Humanoid.TargetPoint)
				script.Parent.Configure.Ammo.Value = originalAmmo
			elseif canrel==true then
				canrel = false
				script.Parent.Handle.Reload:Play()
				wait(script.Parent.Configure.ReloadTime)
				script.Parent.Configure.Ammo.Value = originalAmmo
				canrel = true
			end
		end
		isActive = true
	end)
else
	script.Parent.Activated:Connect(function()
		if canAuto==true then
			repeat
				canAuto=false
				if canfire~=false then
					if script.Parent.Configure.Ammo.Value > 0 or script.Parent.Configure.InfiniteMagSize then
						fire(playerName.Character.Humanoid.TargetPoint)
						script.Parent.Configure.Ammo.Value = originalAmmo
						wait(script.Parent.Configure.ClickTick.Value)
					elseif canrel==true then
						canrel = false
						script.Parent.Handle.Reload:Play()
						wait(script.Parent.Configure.ReloadTime)
						script.Parent.Configure.Ammo.Value = originalAmmo
						canrel = true
					end
				end
			until script.MouseDown.Value==false or script.Parent.Configure.Ammo.Value<=0
			canAuto=true
		end
	end)
end


script.Parent.Unequipped:Connect(function()
	isActive = false
end)