As part of our Airsoft Technology Self-Paced Training Series, this book is for intermediate level airsofters who want to assemble their own M4 CQB AEG from scratch. By building a new TM compatible M4 from ground zero you are free from those limitations imposed by the manufacturer default configuration. We show you how to use metal body parts to build a very solid external structure for the CQB rifle. We then show you how to integrate an air-tight hopup system and high performance V2 gearbox to complete the build process. We even show you how to turn this CQB gun into a single shot only power house We believe that this book and its support materials have everything you need for an informative, interesting, challenging and entertaining Airsoft educational experience. As you read this book, if you have questions, send an e-mail to firstname.lastname@example.org; we will respond promptly. You are encouraged to visit our Web site, www.airsoftpress.com, regularly. We use the Web site to keep our readers and industry clients informed of the latest news on AirsoftPRESS publications and services. Please check the Web site occasionally for errata as well.