Every time I come back from a day at the beach, I make it a point to give everything a thorough wipe-down. It’s just something I can’t skip. I like to use CLP or Ballistol for a solid clean and to keep everything protected. I make sure to really focus on the buffer tube, sling hardware, and optic mounts. I've learned the hard way that rust can sneak up on you in those spots, even if the rest of the rifle looks perfectly fine. Just a light coat of oil seems like a little thing.
