Welcome to the proud family of Desert Tech firearm owners. In acquiring your new MDRX (Micro Dynamic Rifle Ex- treme), you are the owner of the most versatile autoloading rifle in the world. To get the most out of your MDRX rifle, please read this manual from cover to cover before handling and operating the rifle for the first time. CAREFULLY READ ALL OF THE OPERATING INSTRUCTIONS 1 TABLE OF CONTENTS FIREARM SAFETY........................................................................................................................................................................................................................ 5 SPECIFICATIONS ........................................................................................................................................................................................................................... 8 FACTS ABOUT THE MDRX............................................................................................................................................................................................. 10 RIFLE SETUP.......................................................................................................................................................................................................................................... 11 a) Break-In Procedure/Initial Setup/Conversion Kit Installation....................................................................................................................................................11 b) Gas Adjustment.........................................................................................................................................................................................................................................14 c) Handguard Installation...........................................................................................................................................................................................................................15 d) Ejection System (Forward Eject Model)............................................................................................................................................................................................. 16 RIFLE OPERATION.......................................................................................................................................................................................................................18 a) Function Check............................................................................................................................................................................................................................................18 b) Loading..........................................................................................................................................................................................................................................................19 c) Chamber Check (Forward Eject Model).............................................................................................................................................................................................. 20 d) Firing............................................................................................................................................................................................................................................................. 21 e) Reloading.....................................................................................................................................................................................................................................................22 f) Unloading/Clearing.................................................................................................................................................................................................................................. 23 g) Chamber Check (Side Eject Model)....................................................................................................................................................................................................... 24 SIDE EJECTION SIDE SWAP / DISASSEMBLY / REASSEMBLY............................................................................ 25 a) Ejection Side Swap Disassembly.......................................................................................................................................................................................................... 25 b) Bolt Head Removal / Bolt Carrier Group Disassembly................................................................................................................................................................27 c) Ejection Side Swap.................................................................................................................................................................................................................................... 28 d) Bolt Head Installation / Bolt Carrier Group Reassembly............................................................................................................................................................... 29 e) Ejection Side Change Assembly......................................................................................................................................................................................................... 31 2 CALIBER CONVERSION / DISASSEMBLY / REASSEMBLY........................................................................................32 a) Conversion Kit Removal......................................................................................................................................................................................................................................32 b) Bolt Head Removal/Bolt Carrier Group Disassembly................................................................................................................................................................................34 c) Bolt Head Swap.................................................................................................................................................................................................................................................... 35 d) Bolt head Installation/Bolt Carrier Group Reassembly.............................................................................................................................................................................36 e) Magazine Spacer Installation (.223 and .300 BLK) ................................................................................................................................................................................... 37 f) Magazine Catch Installation/Conversion...................................................................................................................................................................................................... 37 g) Magazine Spacer Removal................................................................................................................................................................................................................................ 38 h) Conversion Kit Installation...............................................................................................................................................................................................................................39 DESERT TECH REFLEX OPTIC (DTRO) ............................................................................................................................................................. 42 a) DTRO and DTRO Mount Installation........................................................................................................................................................................................................... 42 b) Using and Zeroing the DTRO......................................................................................................................................................................................................................... 43 ADVANCED DISASSEMBLY / REASSEMBLY.............................................................................................................................................45 a) Bolt Head Disassembly..................................................................................................................................................................................................................................45 b) Bolt Head Reassembly.................................................................................................................................................................................................................................46 c) Gas Block Disassembly.................................................................................................................................................................................................................................47 d) Gas Block Reassembly..................................................................................................................................................................................................................................48 CLEANING AND MAINTENANCE.................................................................................................................................................................................49