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)