Why does my script not work on Filter enabled servers?

I making this gun and it works perfectly in Studio but when in a server with a friend my friend can't see my bullets and killing each other doesn't work.

Could someone explain to me how to make my script work in servers (I used a local script)

-- Starting stuff --
local tool = script.Parent
local player = game.Players.LocalPlayer
local mouse = player:GetMouse()
local character = player.Character
local Barrel = tool:WaitForChild("Barrel")
local enabled = true
local Ammo = tool:WaitForChild("Ammo")
local ammo = Ammo.Value
local SA = tool:WaitForChild("StoredAmmo")
local StoredAmmo = SA.Value
local Reloading = false

--Shooting--
function Shoot()
	if ammo >= 1 and enabled == true and Reloading == false then
	enabled = false
	Firing = true
	isFiring()
	end
end

-- Damage Value --
local Damage = 10,15
local Accuracy = math.random(-5,5)
function isFiring()
	repeat
	local Bullet = Instance.new("Part",workspace)
	ammo=ammo-1
	print(ammo)
	function onTouched(hit)
	if hit.Parent.Name==(player.Name) then
	hit.Parent.Humanoid.Health = hit.Parent.Humanoid.Health - Damage*0
	elseif hit.Name == "Head" then
	hit.Parent.Humanoid.Health = hit.Parent.Humanoid.Health - Damage*2
	Bullet:Destroy()
	elseif hit.Name == "Torso" then
	hit.Parent.Humanoid.Health = hit.Parent.Humanoid.Health - Damage*1
	Bullet:Destroy()
	elseif hit.Name == "Right Leg" then
	hit.Parent.Humanoid.Health = hit.Parent.Humanoid.Health - Damage*0.5
	Bullet:Destroy()
	elseif hit.Name == "Left Leg" then
	hit.Parent.Humanoid.Health = hit.Parent.Humanoid.Health - Damage*0.5
	Bullet:Destroy()
	elseif hit.Name == "Right Arm" then
	hit.Parent.Humanoid.Health = hit.Parent.Humanoid.Health - Damage*0.5
	Bullet:Destroy()
	elseif hit.Name == "Left Arm" then
	hit.Parent.Humanoid.Health = hit.Parent.Humanoid.Health - Damage*0.5
	Bullet:Destroy()
	elseif hit:IsA("Hat") then
	hit.Parent.Humanoid.Health = hit.Parent.Humanoid.Health - Damage*math.random(0.25,2)
	Bullet:Destroy()
	else 
	Bullet:Destroy()
	end
	end
	if ammo == 0 or Reloading then
		Firing=false
	end
	--Bullet--
	game.Debris:AddItem(Bullet,1)
	Bullet.Name= "Bullet"
	Bullet.CanCollide= false
	Bullet.Shape = "Block"
  	Bullet.Material = "Neon"
  	Bullet.BrickColor = BrickColor.new ("Bright yellow")--Colour--
	Bullet.Size=Vector3.new (0.1,0.1,2.5)--Size--
	Bullet.CFrame = Barrel.CFrame*CFrame.new(-1.25,0,0)--Where--
	Bullet.CFrame= CFrame.new(Bullet.Position,mouse.hit.p)
	local Velo = Instance.new ("BodyVelocity",Bullet)
	Velo.velocity =  Bullet.CFrame.lookVector*200--Speed of Bullet--
	Velo.MaxForce = Vector3.new(math.huge,math.huge,math.huge)
	Bullet.CustomPhysicalProperties = PhysicalProperties.new(0.01,0,0,0,0)	
	local weld =Instance.new("Weld",Bullet)
	weld.C0= Bullet.CFrame:inverse()*Bullet.CFrame
	weld.Part0=Bullet
	weld.Part1=Bullet
	local a0 = Instance.new("Attachment")
   	a0.Parent = Bullet
   	a0.Position = Vector3.new(0,.5,0)
   	a0.Name = "Trail Attachment 0"
   	local a1 = Instance.new("Attachment")
   	a1.Parent = Bullet
   	a1.Position = Vector3.new(0,-.5,0)
   	a1.Name = "Trail Attachment 1"
   	local trail = Instance.new("Trail")
    trail.Parent = Bullet
    trail.Attachment0 = a0
    trail.Attachment1 = a1
   	trail.Transparency = NumberSequence.new(0.5,1)
   	trail.WidthScale=NumberSequence.new(0.1,0.1)
	trail.Color = ColorSequence.new(Color3.new(205,150,0))
    trail.LightEmission=0.75
	trail.Lifetime = 0.5
	Bullet.Touched:Connect(onTouched)
	tool.GripForward = Vector3.new(0,-.05,-1)
	tool.Barrel.ParticleEmitter.Enabled = true
	tool.Barrel.PointLightA.Enabled = true
	tool.Barrel.Shot.PlaybackSpeed = 3
	tool.Barrel.Shot:Play()
	local shell = Instance.new("Part")
	shell.CFrame =  tool.Eject.CFrame * CFrame.fromEulerAnglesXYZ(2.5,1,1.25)
	shell.Size = Vector3.new(1,1,1)
	shell.BrickColor = BrickColor.new(24)
	shell.Reflectance = 0
	shell.CanCollide = true
	shell.BottomSurface = 0
	shell.TopSurface = 0
	shell.Name = "Shell"
	shell.Velocity = tool.Eject.CFrame.lookVector * 10 + Vector3.new(math.random(0,0),10,math.random(0,0))
	shell.RotVelocity = Vector3.new(-10,40,30)
	local shellmesh = Instance.new("SpecialMesh")
	shellmesh.Scale = Vector3.new(2,2,2)
	shellmesh.MeshId = "http://www.roblox.com/asset/?id=94295100"
	shellmesh.TextureId = "http://www.roblox.com/asset/?id=94287792"
	shellmesh.Parent = shell
	shell.Parent = game.Workspace
	game:GetService("Debris"):addItem(shell,2)
	wait()
	tool.Barrel.PointLightB.Enabled = true
	tool.GripForward = Vector3.new(0,-.15,-1)
	wait(.005)--FireRate--
	tool.GripForward = Vector3.new(0,-.05,-1)
	wait()
	tool.Barrel.PointLightB.Enabled = false
	tool.GripForward = Vector3.new(0,0,-1)
	enabled= true
	tool.Barrel.ParticleEmitter.Enabled = false
	tool.Barrel.PointLightA.Enabled = false
	--Bullet--
	until Firing == false or Ammo == 0
end

function StopShoot()
	Firing = false
	tool.Barrel.NoShot:Play()
end

--Variable--
function On ()
	Firing = false
	On = true
end

function Off ()
	Firing = false
	On = false
end


--Reloding--
while Reloading do
	script.Disabled = true
end
mouse.KeyDown:connect(function(key)
	if key:lower() == "r" and On and StoredAmmo>=1 or key:upper() == "R" and On and StoredAmmo>=1 then
		local Difference = 30-ammo --If ammo changed change this to Ammo e.g. Ammo=20 then switch the 30 to 20
		Reloading = true
		tool.Barrel.Reload:Play()
		wait(2)
		Reloading = false
		print("Reloaded")
		if StoredAmmo <30 then 
		local FDif = StoredAmmo-ammo
		ammo = FDif + ammo
		StoredAmmo = StoredAmmo-FDif
		print(ammo)
		print(StoredAmmo)
		else
		ammo = Difference + ammo
		StoredAmmo = StoredAmmo-Difference
		print(ammo)
		print(StoredAmmo)
	end
	end
	end)

--Events--
tool.Equipped:Connect(On)
tool.Unequipped:Connect(Off)


--Activated--
tool.Activated:Connect(Shoot)
tool.Deactivated:Connect(StopShoot)