AR-15 Handbook. Erik Lawrence
AR-15 HANDBOOK
AN OPERATIONAL GUIDE TO THE AR-15 RIFLE
by
Mike Pannone and Erik Lawrence
AR-15 HANDBOOK
By Mike Pannone and Erik Lawrence
Copyright 2015 Erik Lawrence,
All rights reserved.All rights reserved.
Print ISBN-13: 978-0-9905131-6-2
eBook ISBN-13: 978-1-941998-58-8
No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by an information storage and retrieval system without permission in writing from the copyright holder. Exceptions to this include reviewers who may quote brief passages in a review to be printed in a magazine, newspaper, or on the Internet.
ATTENTION US MILITARY UNITS, US GOVERNMENT AGENCIES AND PROFESSIONAL ORGANIZATIONS: Quantity discounts are available on bulk purchases of this book. Special books or book excerpts can also be created to fit specific needs. For information, please contact:
Erik Lawrence
21150 Barbour County Highway | Philippi, WV 26416
Although the author has made every effort to ensure the accuracy and completeness of information contained in this book, we assume no responsibility for the use or misuse of information contained in this book, errors, inaccuracies, omissions, or any inconsistency herein. Portions of this manual are excerpts from outside sources but have been validated and modified as necessary.
WARNING, SAFETY, AND TRAINING
WARNING
Firearms are potentially dangerous and must be handled responsibly by individuals. The technical information presented in this publication on the use of the weapon system reflects the author’s research, beliefs, and experiences. The information in this book is presented for academic study only. Neither the author nor the publisher assumes any responsibility for the use or misuse of information contained in this book.
SAFETY NOTICE
Before starting an inspection, ensure the weapon is cleared. Do not manipulate the trigger until the weapon has been cleared of all ammunition. Inspect the chamber to ensure that it is empty and no ammunition is present. Keep the weapon oriented in a safe direction when loading and handling.
TRAINING
Training should be received from knowledgeable and experienced operators on this particular weapons system.
ACKNOWLEDGEMENTS
To all the American citizens who lawfully and responsibly exercise their 2nd Amendment rights under the U.S. Constitution. You are the world’s truest example of a free and vigilant people.
“The bravest are surely those who have the clearest vision of what is before them, glory and danger alike, and yet notwithstanding, go out to meet it.”
Thucydides, 471 B.C.
CHAPTER 1
RIFLE SPECIFICATIONS
The AR-15 Carbine/Rifle is a .223 Remington/5.56x45mm lightweight air-cooled, gas-operated, magazine-fed, shoulder-fired rifle. The AR-15 fires from a closed bolt in semi-automatic mode while the military M4 variants are either semi-automatic, burst, or full-automatic.
Figure 1-1 - AR-15A2 HBAR
CALIBER: .223 Remington or 5.56X45mm NATO
WEIGHT WITHOUT MAGAZINE: 8.5 pounds (2.94 kg)
EMPTY 30-ROUND MAGAZINE: 0.25 pounds (0.11 kg)
LOADED 30-ROUND MAGAZINE: 1 pound (0.45 kg)
OVERALL LENGTH: 39 inches (1 meter)
BARREL LENGTH: 20 inches (51 cm)
BORE CHARACTERISTICS: Hard chrome-lined, 6 Lands, 1:9
METHOD OF OPERATION: Gas-direct system; rotating bolt
MUZZLE VELOCITY: 3,200 feet/second (975 meters/second)
EFFECTIVE RANGE: 600 meters
FRONT SIGHT: Adjustable front
REAR SIGHT: M16A4 target-style sight adjustable for windage and elevation to 600 meters
SIGHT RADIUS: 20 inches (51 cm)
FIRE CONTROL SELECTION: Safe – Semi-automatic
UPPER RECEIVER: Flat top with detachable carrying handle
Figure 1-2 - AR-15A2/A3
CALIBER: .223 Remington or 5.56X45mm NATO
WEIGHT WITHOUT MAGAZINE: 7.0 pounds (3.2 kg)
EMPTY 30-ROUND MAGAZINE: 0.25 pounds (0.11 kg)
LOADED 30-ROUND MAGAZINE: 1 pound (0.45 kg)
LENGTH: 29.8 inches to 33 inches (collapsed/extended)
BARREL LENGTH: 16.1 inches (41 cm)
BORE CHARACTERISTICS: Hard chrome-lined, 6 Lands
METHOD OF OPERATION: Gas-direct system; rotating bolt
MUZZLE VELOCITY: 2800 feet/second (884 meters/second)
EFFECTIVE RANGE: 600 meters
FRONT SIGHT: Adjustable front
REAR SIGHT: Dual apertures (0-200m and 300-600) target-style sight adjustable for windage and elevation to 600 meters
SIGHT RADIUS: 14.5 inches (37 cm)
FIRE CONTROL SELECTION: Safe – Semi-automatic
UPPER RECEIVER:
A2 Model- Non-removable carrying handle
A3 Model- Flat top with detachable carrying handle
The barrel rifling twists vary from the original 1 turn in 12 inches (1/12) on the first AR-15 series guns shooting 55-grain bullets, to the current 1/7 or 1/9 twist on the M16A2/A4 service rifle and M4 Carbine. The faster twist is necessary to stabilize the longer and heavier SS109 62-grain bullet with steel penetrator used in M855 ammunition.
CHAPTER 2
DIRECT-IMPINGEMENT GAS SYSTEM THEORY
The AR-15 family of weapons uses a direct-impingement gas system which does not utilize a gas piston, Figure 2-1. When a round is discharged, the bullet passes the gas port in the barrel where gas is tapped off into the gas tube and redirected back to the bolt carrier key, Figure 2-2. The gas enters the gas carrier key and is channeled into an expansion chamber in the bolt carrier. The gas is trapped between the rear portion of the expansion chamber, and the gas rings towards the rear of the bolt. As the gas expands, it is contained by the bolt gas rings and acts on the bolt carrier, pushing it to the rear, and operating the bolt cam pin in the bolt carrier’s cam surface. As the bolt carrier moves to the rear, the bolt rotates 22.5 degrees clockwise, unlocks, and begins extraction of the expended cartridge case.
VARIANTS
Numerous variants are available throughout the country and world, and nearly all work the same way. The key to keeping this system running reliably, with minimum maintenance, is ensuring that all the critical parts related to extraction and ejection and prone to wear are serviceable. These parts are extractor and spring, ejector and spring, gas rings, and buffer spring. If all these are in good serviceable