Real Avid's Master Series is a definite page-turner for anyone that likes to DIY their rifle. This booklet is a complete guide to help you to get to know your AR15, as well as offering an 82pg glossary of terms. Booklet's Featured Topics: The history of the AR15 Platform Operating Systems Explanation of the differences between .223 & 5.56 Common Cartridges in the AR15 A Break Down of the Tools you'll need to Modify your AR15 Procedures What is Headspace & Why is it so important? Upper Receiver/Barrel Modifications Lower Receiver/Stock Modifications