Moving down the weapon, we run into the castle nut. This is another item that some manufacturers tend to skimp on. The military calls for staking of the castle nut in the same way that they demand staking of the carrier key. Some people feel that a dab of thread locker will serve the same purpose, but I've taught courses where those weapons have had their castle nuts loosen up, or in some cases even back off enough to allow the stock to rotate.

Staking serves a valid purpose,and Charles Daly does it nicely. The below picture shows two points on the castle nut that are well staked.