I haven't taken a magazine other than American Rifleman and their comanion Shooting Sports mag for decades now...

...any out there that cover gunsmithing?

Ideally, there'd be a Taunton Press Fine Woodworking/Fine Homebuilding equivalent.

I believe some of the Professional Smiths could fill you in far better than I, but I think you can become an associate member of the Custom Gunmakers Guild and then be eligible to receive their gunsmithing/gunmaking publication.

In addition, although not a magazine, AGI puts out a number of video tapes on various gunsmithing topics. You could purchase one a month if you so desired.

Every once in awhile Rifle Magazine and its sister publication Reloader will carry an article on some sort of work involved with guns. I recall articles on installing a leather covered pad, checkering and stocking.

Blue

Don't Know that it is the equal of Fine Woodworking, but there is one.
http://www.american-gunsmith.com/