The Master of the AR-15 Has Done It Again! The AR-15 has become America's favorite rifle-and no one knows it better than Patrick Sweeney. Now, in Volume 3 of his best-selling series on the AR, Sweeney unlocks the mysteries behind the piston AR. From factory-stock rifles to do-it-yourself conversions, if there's anything you want to know about the latest generation of the AR-15s, you'll find it in Gun Digest (R) Book of The AR-15, Volume 3. It's All Here! Piston designs Conversions from direct impingement to piston operation New manufacturers: H&K, Sun Devil, CMMG, among others Magazines and other accessories And much, much more! Whether you're buying your first AR or building one from the ground up, there's no better reference than Sweeney's AR series from Gun Digest (R) Books. And now, with Gun Digest (R) Book of The AR-15, Volume 3, you too, will be an expert on the most popular rifle in America!