Ok, so I'm building my first AR, and I just got the LPK and a standard 6 pos stock. I've installed the LPK and also the stock, but I don't have the right tool to tighten the castle nut, so I'm not quite done (it's hand tight at the moment). So, when I finally get the tool to tighten the castle nut, should I use locktite? Or is it unnecessary? Thanks!