Or just practice with one of these first: http://www.80percentarms.com/products/0-billet-ar-15-lower-receiver http://www.80percentarms.com/products/0-billet-ar-

Or just practice with one of these first: http://www.80percentarms.com/products/0-billet-ar-15-lower-receiver http://www.80percentarms.com/products/0-billet-ar-15-lower-r... ^_^ ("0% BILLET AR-15 LOWER RECEIVER"). Or scrap aluminum, this sort of thing really isn't that hard if you've got some manual dexterity, but, well, that's why the classic first wood shop project is something like a bread board.