Re: Para Ordnance Lower
Second opinion here; Keep the Zediker book, it's invaluable, especially for a first time builder. Glen's a proven source, and is a good builder himself. The books packed with large, very clear pictures that will guid you through every step of the build, illustrate various options, and discuss why you may or may not want to choose one over the other. Lots of good ideas in there.
The 6x45's a great little cartridge, especially for a hunter. Little bit more punch that a standard 223 for game, but not really as good a cartridge for long range use, considering the .224" bullets that are available today. Very easy to load, and you can form cases without even realizing you're doing it. Good choice here.