Re: AR builf for beginners questions
I 've built several lowers and recently an upper, barrel wrench came with the forend I bought, nothing expensive about it.
Anywho, if you want to buy a complete upper, you'll also need a bolt carrier assembly.
As for the lower, low buck, get a basic lower parts kit, not so low buck, get one minus FCG, and order FCG or your choice, everybody loves Geissele. Then get stock kit of your liking, there are many availible with stock, receiver extension (buffer tube), buffer, spring, castle nut if required, otherwise buy all those parts seperate.
Tools required for assembling a lower, roll pin punches, small hammer, allen/hex wrench for pistol grip, and spanner wrench if getting a carbine stock. To make it easier roll pin starter punches, action/vise block for lower receiver. Armorer's wrench puts a bunch of neccesary tools in one place, but has more for the upper than the lower. Get yourself a book, schematic, or buddy if your AR knowledge is limited, its pretty simple.