V-Line Closet Vault Plus Gun Cabinet 51653-S-PLUS with Peg Board

There's tons of in the wall safes on the market. Most cost about a third what this does. But there's exactly one that looks like it is part of the house, is tall enough for longer rifles (and honestly, if they made one even taller, I'd have gotten it), is well built, and has only a mechanical lock. If you're going to cut a giant hole in your wall, get the one that will last the life of the house and not rely on batteries, backup keys, circuit boards, etc.

Wall safe

Great use of space and a well built product