I want gun to stop firing when inside a block?

I'm making a gun. But a big gameplay issue is the ability to put the gun through a part, and be able to shoot out the other side. I'm using raycast here is my script. It's a local script btw.

local tool = script.Parent
local user
local cooldown = false
local ammo = 18
local debounce = false
local canfire = true
tool.Equipped:connect(function(mouse)
    user = tool.Parent
    mouse.Button1Down:connect(function()
        if cooldown == false and ammo > 0 and canfire == true then
            ammo = ammo - 1
            tool.Handle.Fire:Play()
            tool.Name = "|Pistol| ["..ammo.."]"
            cooldown = true
            local ray = Ray.new(tool.Handle.CFrame.p, (mouse.Hit.p - tool.Handle.CFrame.p).unit*300)
            local hit, position = game.Workspace:FindPartOnRay(ray, user)
            local humanoid = hit and hit.Parent and hit.Parent:FindFirstChild("Humanoid")
            if humanoid then
                if hit.Name == "Head" then
                    humanoid:TakeDamage(55)
                end
                if hit.Name == "LeftLeg" or hit.Name == "RightLeg" then
                    humanoid:TakeDamage(10)
                end
                if hit.Name == "LeftArm" or hit.Name == "RightArm" then
                    humanoid:TakeDamage(10)
                end
                humanoid:TakeDamage(30)
            end

            local distance = (position - tool.Handle.CFrame.p).magnitude
            local rayPart = Instance.new("Part", user)
            rayPart.Name          = "RayPart"
            rayPart.BrickColor    = BrickColor.new("Bright red")
            rayPart.Transparency  = 0.5
            rayPart.Anchored      = true
            rayPart.CanCollide    = false
            rayPart.TopSurface    = Enum.SurfaceType.Smooth
            rayPart.BottomSurface = Enum.SurfaceType.Smooth
            rayPart.formFactor    = Enum.FormFactor.Custom
            rayPart.Size          = Vector3.new(0.2, 0.2, distance)
            rayPart.CFrame        = CFrame.new(position, tool.Handle.CFrame.p) * CFrame.new(0, 0, -distance/2)
            game.Debris:AddItem(rayPart, 0.1)
        end
        if ammo == 0 then
            if debounce == false then
                debounce = true
                tool.Name = "Reloading"
                tool.Handle.Reload:Play()
                wait(2.5)
                ammo = 18
                tool.Name = "|Pistol| ["..ammo.."]"
                debounce = false
            end
        end
        mouse.KeyDown:connect(function(key)
            if key == "r" and debounce == false then
                debounce = true
                tool.Name = "Reloading"
                tool.Handle.Reload:Play()
                wait(2.5)
                ammo = 18
                tool.Name = "["..ammo.."]"
                debounce = false
            end
        end)
    end)
end)
while true do
    if cooldown == true then
        wait(0.25)
        cooldown = false
    end

    wait()
end