The Gun Digest Book of the AR-15, Volume III

290 Pages·2010·25.32 MB·English

by  Patrick Sweeney

The Master of the AR-15 AR-15
Gun Digest®
Book of
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Patrick Sweeney
All the Latest in Guns, Optics and Accessories
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Gun Digest®
Book of
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Volume 3
PPAATTRRIICCKK SSWWEEEENNEEYY
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Copyright ©2010 Patrick Sweeney
All rights reserved. No portion of this publication may be reproduced or
transmitted in any form or by any means, electronic or mechanical, including
photocopy, recording, or any information storage and retrieval system, without
permission in writing from the publisher, except by a reviewer who may quote brief
passages in a critical article or review to be printed in a magazine or newspaper,
or electronically transmitted on radio, television, or the Internet.
Published by
Gun Digest® Books, an imprint of F+W Media, Inc.
Krause Publications • 700 East State Street • Iola, WI 54990-0001
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Library of Congress Control Number: 2010924666
ISBN-13: 978-1-4402-1376-2
ISBN-10: 1-4402-1376-3
Cover Design by Tom Nelsen
Designed by Paul Birling
Edited by Dan Shideler
Printed in United States of America
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DEDICATION
As always, and ever, for Felicia.
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ACKNOWLEDGEMENTS
As the story goes, Winston Churchill was broke. Ammo, ammo. Wolf provided plenty, Black Hills
He’d been essentially tossed out of the government, and even more; Alexander Arms sent a metric vestload, and
the great depression was raging. So he wrote. He wrote Hornady continues to amaze and embarrass me on the
a biography of an ancestor, John Churchill, the 1st Earl amount of ammo they are willing to send.
of Marlborough, but his crowning achievement was On the new piston front, Jason Adams sent his
his History of the English Speaking Peoples. It was not system, info, instructions and more. Jeff Overstreet of
published until after WWII, but that wasn’t a problem as CMMG allowed me to spend entirely too much time
he was also a well-paid lecturer and public speaker. The dissecting his piston system and then thrashing it on his
manuscript of History of the English Speaking Peoples range with all the ammo I cared to feed it. Now that is
was typed by a secretary as he dictated it. That’s right, confi dence in a system.
he wrote a multi-volume book out of his head. I’m sure As for Rock River: thank you. An Operator Elite, a
he did research from the family library, as any decent stock M4gery and a 9mm lower, all to inform the readers
landed gentry house of the time no doubt had books and extol the virtues of Rock River fi rearms. You are the
contemporaneous to the period he was speaking on. But, soul of generosity.
holy cow, to do it all off the cuff, as it were. What a guy! Frank DeSomma, my apologies for taking this long to
I did not dictate this book. I typed it, and I had help review your rifl es. It was worth the wait; they are bomb-
from the people who make the stuff you’re reading proof and run like tops.
about. Dave Beatty, as always, was quite helpful on Last, Colt. I know, as I’ve said many a time, it is
matters related to billet machining and Sun Devil. Todd fashionable to bash Colt. But they still make the gold
Tuttle at PWS was more than helpful, and I still get a standard of DI-driven carbines and rifl es. They managed
chuckle when I look at their poster of the tactical Corgi. to fi nd one to send me, and they also allowed me to
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N To Mark Malkowski: if not for you and Stag, I’d be wander the factory, poking my nose into things probably
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G is to manufacture an AR. To all, my very sincere thanks.
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E Eric Kincel of Vltor and Adam Treischman of Spirit
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N gear they make and how they make it. And Les Baer April, 2010
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explaining what goes into them.
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DEDICATION .........................................................................................................III
ACKNOWLEDGEMENTS ..........................................................................................IV
INTRODUCTION ......................................................................................................6
CHAPTER ONE: What Are We Doing Here? ...............................................................8
CHAPTER TWO: What Is This Piston Stuff, Anyway? .................................................16
CHAPTER THREE: HK Engineering ..........................................................................30
CHAPTER FOUR: LWRCI .......................................................................................44
CHAPTER FIVE: The Adams Arms Piston Conversion ................................................60
CHAPTER SIX: The Stag Arms M8 ..........................................................................70
CHAPTER SEVEN: The PWS ..................................................................................82
CHAPTER EIGHT: CMMG ......................................................................................90
CHAPTER NINE: Other Piston Guns and the Future ..................................................98
CHAPTER TEN: Patriot Ordnance Factory ...............................................................106
CHAPTER ELEVEN: The Ruger SR556 ....................................................................118
CHAPTER TWELVE: Converting a Direct Impingement Carbine to Piston ....................132
CHAPTER THIRTEEN: Rimfi res and Pistol-Caliber Conversions ...................................138
CHAPTER FOURTEEN: New Calibers ......................................................................164
CHAPTER FIFTEEN: Magazines .............................................................................178
CHAPTER SIXTEEN: Retro’s, High-Tech and Confl icting Desires.................................188
CHAPTER SEVENTEEN: Colt in the New Era ...........................................................214
CHAPTER EIGHTEEN: DSA ....................................................................................228
CHAPTER NINETEEN: Spirit Gun Mfg. ....................................................................236
CHAPTER TWENTY: Les Baer .................................................................................246
CHAPTER TWENTY-ONE: Noveske .........................................................................254
CHAPTER TWENTY-TWO: The DPMS 6.8 ................................................................260
CHAPTER TWENTY-THREE: The Rock River Operator ...............................................264 C
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CHAPTER TWENTY-FOUR: Wilson Combat 6.8 ........................................................270 N
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CHAPTER TWENTY-FIVE: One Rifl e to Rule Them All ...............................................276 N
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CONCLUSION ......................................................................................................284 S
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5
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better.”
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K In the fi eld of mechanical engineering, there is a concept called “mature
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DI framework. An example: the Roman gladius. A short sword, sort of like a
N machete sharpened on both edges, the gladius was the tool of Roman conquest
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and order. With a blade two feet long at most, it wasn’t to the current record-holder: the British Brown Bess
an imposing weapon. Unless, of course, it was being musket. Introduced in 1722 as the Land Pattern musket,
wielded by one in a cohort of legionaries who were it served essentially unchanged until replaced in 1838 by
closing in on your formation. The gladius was meant a percussion-cap model of pretty much the same rifl e.
as a team weapon. The cohort (the single line in each If we take things up to the point where the British
century) were behind their shields, and each legionary adopted a rifl ed musket in the Enfi eld Pattern 1851 rifl ed
was trained to support the guy next to him. You weren’t musket, that means the Brown Bess, or a derivative of it,
going to fi ght one, you were going to fi ght them all. served for 129 years. That’s a lot to ask, but the M2HB
As good as the gladius was, if the locals (think: big will match it in the year 2050.
German tribesmen) broke the line, then each legionary What does all this have to do with the AR-15? Simple:
was at a disadvantage one-on-one. Unless, of course, he it does not appear likely to be replaced any time soon.
remembered the training he’d been given on using his As much as some love to hate it, nothing seems
shield as part of his fi ghting. ready to push it off the platform just yet. What everyone
However, put a Roman legionary up against a foppish seems intent on is tuning it up, improving performance,
French courtier, and the Roman was toast as soon as the basically fi ddling around the margins – which is what
pomaded frenchie fi gures out how to get his light, fast, we’ll be looking at in this volume. In earlier volumes we
pointy stabbing blade past the tired Roman’s shield. covered the various makers. In the AR-15 Gunsmithing
The lesson has to be learned again and again. When volume we’ve looked at how to work on the rifl e, and
smokeless powder-using, magazine-fed rifl es were new, what things you can and cannot change. Here, we’ll be
the idea of a rifl e company commanding all it saw before looking at three main fi elds, and the things that relate:
it out to 1,000 yards was very appealing. A couple of the piston system, different calibers, and aiming options.
decades later, in the trenches of WWI, a rifl e with a 29- Cast your mind ‘way back to the 1980s: the bad hair,
inch barrel and a 16-inch bayonet was not very handy, the dodgy music, the cars that (in many cases) sucked.
and the ability to hit targets at 900+ yards was next to At the same time, the Army was looking to do two
useless. What you needed on a trench raid was a good things: improve the M16 and replace it. The replacement
pistol, a shotgun, and an entrenching tool with one side was the SPIW, a combination weapon that the user
of the blade sharpened. And a bag of grenades. could choose to fi re either fl echettes (small, dart-like
In the history of small arms, some have lasted longer projectiles) at hyper velocities, or grenades. Yes, both
than others. In the American arsenal, the AR-15/M16 from the same weapon.
has lasted a long time. Depending on just when you Neither worked on its own; the two together worked
think it was introduced, adopted, accepted or issued, even less well (one sample produced for the testing was
it has passed its 40th birthday. It’s closing in on 45 inspected and deemed too unsafe even to test-fi re) and
years. The M1 Garand lasted from 1936 to 1958. The the improved M16 became the new rifl e. One big change
M1 Carbine from 1940 to 1958. The 1911 pistol, 1911 was better sights, for more-accurate long-range shooting.
to 1985. One that is overlooked by many is the Colt/ Which was ironic, as by then the Army had given up on
Browning 1917 machine gun, from 1917 to 1960. The precise long-range shooting with rifl es, but that is a story
winna and still champeen in American service, however, to be covered in the appropriate chapter.
is the M2HB. From 1921 to the present day, the big .50 We’ll be looking at pistons because that is the big
has been smacking America’s enemies and smacking drawback of the AR-15: the direct impingement gas
them hard, at a pace so sedate it can only make the blood system. But it’s its greatest strength, too. Yes, that is a
run cold on the other end. schizophrenic statement, but that pretty much describes
The much-beloved-by-some M14? A paltry 1958 to the whole AR-15/M16/M4 mess: yes/no, good/bad, I
1968. Oh, some are still in service, but only because the love you/I hate you, etc.
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government still has them. There are few spare parts, Oh, and prepare to leave your preconceived notions T
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no trained armorers, and the only ones who love it do at the door, as there are a lot of things you “know” about
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so because they love the cartridge more than anything. the AR that you really don’t. No offense intended.
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WHAT ARE WE
DOING HERE?
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There’s an empty spot waiting for you.
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A wheelock, the highest-tech fi rearm of
the fi rst half of the sixteenth century.
OK, granted, the AR universe is in fl ux. Companies cartridge that doesn’t fi t the magazine platform, you can
are popping up right and left (and dying in the sun, in do it all starting with the same basic upper and lower.
many cases) and the plethora of painted ARs to be seen You can also swap from the original direct gas
on the range is like never before. So what? Wasn’t it impingement system to a piston system, and back. (Well,
always like this? And what’s so special about now? some piston systems would make switching back a bit
Simple: the AR has fi nally become the ultimate tough, but that is a small detail.)
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home hobby gun. You can build an AR in any No other rifl e in history has been able to do this. The H
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confi guration from an entry gun, with a 10.5-inch Mauser came close, being able to be chambered in a T
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barrel in 5.56 (with appropriate paperwork, of course) whole host of cartridges, but to do any of the work you R
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to a twenty-inch barreled sniper rifl e in 6.5. You can had to be a gunsmith. Not so with the AR-15. W
have iron sights, or a scope; you can have a stock that And yes, I’m going to call it the AR-15, unless a E
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adjusts or doesn’t; and you can have a trigger that is specifi c rifl e we’re discussing or thrashing has a different O
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breath-light or pliers-heavy. name on it. We’re going to dive deep into the AR in the G
All this beginning on the same upper and lower, 21st century. H
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without even having to get a special model to handle That means looking at all the calibers you can get R
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something out of the ordinary. Unless you’re going to a (or at least, that I can lay hands on) and wrestle into
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