Small Arms is one of my favorites. There is an NRA app. USA Carry, but I assume you already have it. FirearmsTalk and Glock Forum if you want more choices. GunDism2 is pretty neat,it shows you how to disassemble and reassemble different guns. It has a few free ones. You can also create shortcuts from webpages. Try going to imfdb.org and creating a shortcut. That site has a lot of guns info from TV shows and movies.