How would you visualize a raycast (laser/bullet)?

local replicatedStorage = game:GetService("ReplicatedStorage")
local weaponRemoteEvents = replicatedStorage.remoteEvents.weaponRemoteEvents

weaponRemoteEvents.shootEvent.OnServerEvent:Connect(function(player, mousePos, bulletTravelDistance, toolHandle, damage, toolName)
    local rayParams = RaycastParams.new()
    rayParams.FilterDescendantsInstances = {player.Character}
    rayParams.FilterType = Enum.RaycastFilterType.Blacklist

    local ray = workspace:Raycast(toolHandle.CFrame.p, (mousePos - toolHandle.CFrame.p) * bulletTravelDistance, rayParams)

    if ray then
        local model = ray.Instance:FindFirstAncestorOfClass("Model")
        if model then
            if model:FindFirstChild("Humanoid") then
                model.Humanoid.Health -= damage
            end
        end
    end
end)

Here is the code for the gun. I've tried so many ways to get a working visualizer but I just can't seem to get it to work. Please help. Also here are what the params are:

player = local player
mousePos = player:GetMouse().Hit
bulletTravelDistance = 300
toolHandle = toolHandle part
damage = 10
toolName = ar