Why doesn't my ray casting script work in game but in studio?

I'm not really good at raycasting so I don't know how to do stuff. Really I wanted to use Filtering Enabled but I can't access my weapon with a server script due to it being in the camera unless I learn. Any help would be appreciated

function createRay()
	
			local muzzle = gun[gun.Name].Flash
	local ray = Ray.new(mouse.Hit.p,muzzle.CFrame.lookVector*999)
	local hit,pos = workspace:FindPartOnRayWithIgnoreList(ray,{char})
	
	if hit then
			local human = hit.Parent:FindFirstChild("Humanoid")
			if human then
			print(hit.Name)
			if human.Health >0 then
			player.PlayerGui.HUD.Crosshair.Hit:Play()
			player.PlayerGui.HUD.Crosshair.Frame.Hitmarker.Visible = true

			if hit.Parent == "Head" then
			human:TakeDamage(s.dmg * s.multi)
			
			elseif hit.Parent:IsA("Part") then
			human:TakeDamage(s.dmg * s.damage)
			
			elseif hit.Parent:FindFirstChild("Humanoid") then
			human:TakeDamage(s.dmg)

			
			end
			end
			end
			end
end

Sometimes the ray wouldn't detect the head even though I'm aiming straight at it. Not sure why? Even the Upper Torso. Maybe I should try R6 instead