The American Rifleman is my overall favorite, mainly for the accuracy testing, an average of ten, 5 shot groups with at least 3 different kinds of ammo, plus they give the conditions the firearm was tested, a lot of the historical articles well researched and informative.
After that.
1) Handloader magazine, it also has articles on firearms, and how to make the best ammo for them, especially if ammo is no longer available, although for a short time it seemed like the Ross Seyfreid handloading tips magazine, as he would have 3-4 articles at a time. I have handloader going back to the first copy in I believe 1976, a treasure trove.
2) Precision shooting magazine, Dealing exclusively with extreme rifle accuracy. The columnists are some of the best and the best in the world, Like G David Tubb, Derrick Martin etc...
3) Shooting Sports magazine from the NRA, it is now only available as a paid subscription, but has good info, if you like NRA tournaments or Olympic/International shooting.
4) Rifle magazine, a step brother of Handloader magazine, you can even get an online subscription.
5) SWAT, mainly because a friend of mine is a columnist and one of my rifles was in it, soon another one will be in it. For those that don't know, the Head guys house burnt down with lots of the information lost, but all is recovering.
6) The Shooting Journal, if you like fine rifles and shotguns, with some historical pistols thrown in, and some good classifieds.
7) American Handgunner, great pics, but short on new stuff these days, I range officered Cameron Hopkins when he was shooting Ipsc, and don't have high regard for him, and that clouds my view of the mag. I do buy it when I see something that interests me.

Shooting Times, generally above Guns and Ammo, their reloading section is usually a notch above most.
These are the ones that come to mind.