Customize the Ruger 10/22

By James E. House and Kathleen A. House

Welcome to the most complete resource available for the Ruger 10/22!

In this 2nd edition of Customize the Ruger 10/22, expert advice leads you through the process to modify and customize your Ruger 10/22, and includes:

• Step-by-step installation instructions with more than 300 detailed photos
• Coverage of models introduced since the previous edition
• Completely updated list of suppliers of aftermarket parts

Plus, you'll find performance testing of the popular new Takedown Model and a 10/22M converted to .17 HMR!

With installation instructions, performance evaluations and expert advice, Customize the Ruger 10/22 2nd Edition is the most comprehensive do-it-yourself guide available for upgrading and customizing America's favorite .22.

• Language: English
• Publisher: Gun Digest Books
• Release date: Oct 29, 2015
• ISBN: 9781440245565

James E. House

J.E. House is Scholar in Residence, Illinois Wesleyan University, and Emeritus Professor of Chemistry, Illinois State University. He received BS and MA degrees from Southern Illinois University and the PhD from the University of Illinois, Urbana. In his 32 years at Illinois State, he taught a variety of courses in inorganic and physical chemistry. He has authored almost 150 publications in chemistry journals, many dealing with reactions in solid materials, as well as books on chemical kinetics, quantum mechanics, and inorganic chemistry. He was elected Professor of the Year in 2011 by the student body at Illinois Wesleyan University. He has also been elected to the Southern Illinois University Chemistry Alumni Hall of Fame. He is the Series Editor for Elsevier's Developments in Physical & Theoretical Chemistry series, and a member of the editorial board of The Chemical Educator.

Book preview

CHAPTER 1

HISTORY AND CURRENT VERSIONS OF THE RUGER 10/22

Some products reflect an excellence of design that becomes synonymous with the company that produced them. Although Sturm, Ruger & Company might be considered a relative newcomer in the field of firearms manufacturing, it has established itself as a company that produces excellent firearms that are durable and represent good value. One of the products that has gone a long way toward establishing the reputation of Sturm, Ruger & Company is the .22 LR autoloading rifle known as the Model 10/22.

Even though the stock 10/22 performs well, it is the fact that so much can be done to modify the 10/22 that has helped make it an American icon. It is truly a tinker toy rifle that can be configured to suit almost any taste or purpose. This idea is well illustrated in the pages of this book, which is devoted to tinkering with the 10/22. It must be emphasized, however, that although we describe many modifications to a 10/22, the authors are not professional gunsmiths, and the information is presented for educational purposes only. Any person who modifies a firearm does so at his or her own risk, and usually voids any warranty from the manufacturer. Safety is the responsibility of the person who owns, modifies and uses any firearm. Neither the authors nor the publisher accept any responsibility for any issues that may arise as a result of the use of the information in this book.

The Ruger 10/22 Carbine has resulted in a huge aftermarket industry. (Photo courtesy of Ruger)

STURM, RUGER & COMPANY, INC.

From a modest beginning about 65 years ago, Ruger has become one of the largest manufacturers of firearms in this country. The initial product, a .22 caliber semiautomatic pistol that originally sold for $37.50, was introduced in 1949. Some manufacturers of firearms produce only handguns, others produce rifles and shotguns, but Ruger produces a comprehensive line of firearms that includes all of these types. Moreover, the handguns include not only numerous models of rimfire semiautomatics but also a wide variety of centerfire semiautos, including striker fired models and others patterned after the famed Colt 1911 .45 Auto. The Ruger revolvers have from the beginning included both rimfire and centerfire single action models, and the current offerings of this type are numerous. Double action revolvers are also well represented by models that are suitable for concealed carry, sporting and law enforcement uses.

Over the years, Ruger has also produced double barrel shotguns in both over-and-under and side-by-side models. Centerfire rifles have been produced in a bewildering array of models that include the bolt action Model 77, 77 Mark II and Hawkeye versions, as well as the elegant single shot No. 1 and numerous models of semiautomatics. For several years, Ruger produced the Model 96 lever action rifles in 44 Magnum, .22 LR, .22 WMR and .17 HMR calibers, which have since been discontinued. Rimfire rifles produced by Ruger include the elegant Model 77 bolt action sporting rifles in .22 LR, .22 WMR, .17 HMR, (the 77/22, 77/22M and 77/17M, respectively). With the list price of a Model 77 being over $900, Ruger’s recent entry into the rimfire field is the bolt action American Rimfire that is available in .22 LR, .22 WMR and .17 HMR calibers. The American has a list price of $339, but has many features that belie its price.

Although the Ruger 10/22 Carbine (left) remains popular, the Takedown version (right) has gained rapid acceptance.

Although these offerings include something for shooters in almost any type of shooting sport, it should be made clear that the first rimfire rifle offered by the Sturm, Ruger & Company was the .22 semiautomatic that has arguably become the most successful rimfire rifle of all time. That little rifle, known as the Model 10/22 Carbine, was introduced in 1964. In the intervening 50 years, over five million 10/22s have been produced. Moreover, the 10/22 is produced in numerous versions that span the range from plinking rifles to target models to varmint rifles chambered for the .22 LR caliber, and a .22 WMR version was offered for several years.

A pistol known as the Charger was introduced in 2007. In essence, it is a 10/22 action with a 10-inch barrel and a pistol grip. The BX-15 magazine has a capacity of 15 rounds, but because it is separate from the grip and there is no loaded chamber indicator, the Charger is not legal in all jurisdictions. Although not the subject of this book, the Charger is amenable to many of the same alterations that can be made on the 10/22.

The Charger pistol utilizes the same action as the 10/22. (Photo courtesy of Ruger)

With a firearm that has been as successful and produced in such numbers as the Ruger 10/22, there are numerous dates that are significant with regard to the variants produced and when certain changes were made. The accompanying table summarizes some of the most important dates related to events in the long life of the Ruger 10/22. In addition to the events listed, there are many others in which minor changes were made in sights, markings, etc., which even though they are of interest to collectors, are too numerous to list in detail in this book.

One of the numerous variants of the Ruger 10/22 Carbine has a synthetic stock and a stainless steel barrel. (Photo courtesy of Ruger)

RUGER 10/22 VERSIONS

Although they are discussed in more detail later in this chapter, this section presents an overview of the several versions of the 10/22 that are available at the present time. The original Ruger 10/22, known as the Carbine, has distinctive styling. Being a true carbine and having a barrel that measures only 18.5 inches in length, it also sports a stock that has carbine styling. The butt plate is curved, and the forearm is circled with a barrel band. Loosely interpreted, a 10/22 carbine bears some resemblance to the military M1 Carbine.

In addition to the Carbine version of the 10/22, there are also variants known as the Rifle (introduced in 2004 and discontinued as a factory version in 2006 but still available as a distributor exclusive) that has a 20-inch barrel; the Sporter that has an 18.5-inch barrel and checkered walnut stock; the Tactical that has a 16.12-inch barrel and a flash suppressor; and the version with a heavy 20-inch barrel that is known as the 10/22 Target.

In September 2005, Ruger announced the introduction of yet another version of the 10/22. This version, officially known as the 10/22 Compact Rifle, has a 16.5-inch barrel and a scaled down stock that gives a length of pull of only 12.5 inches. The 10/22 Compact Rifle has a stock that resembles that of the Rifle in that there is no barrel band and the butt plate is flat rather than curved like that on the Carbine. Currently, several versions of the 10/22 are marketed with a LaserMax sight installed that replaces the barrel band. A version of the 10/22 was available in .22 WMR caliber from 1998 to 2006 and a model in .17 HMR was introduced but, because of problems with bolt velocity as a result of the pressure curve, that model was never released.

At the forward end of the forearm, a barrel band circles the stock and barrel.

The butt plate on the Ruger 10/22 has the unique carbine style.

In 2012, a version of the 10/22 known as the Takedown model was introduced. It consists of two major assemblies that can be separated. One component includes the stock and action, the other incorporates the barrel and forearm. The units are held together with a locking system that is described later in this chapter. Like the Carbine, the Takedown utilizes a barrel measuring 18.5 inches in length. It is available as a factory item with a black polymer stock, but numerous other configurations are available as distributor exclusives.

Although current Ruger 10/22 products include the Carbine, Target, Sporter, Tactical, Compact Rifle and Takedown models, there have been a large number of small changes over the years. These include changes in sights, stocks and other parts, but the basic design has remained the same. Two recent significant alterations involve the change to a polymer housing for the trigger assembly and an extended magazine release. It is neither possible nor necessary to give a complete description of these variants, although that information would certainly be of interest to the serious collector. The most complete catalog of Ruger 10/22 variants in the first 30 years of its production is the book by William E. Workman (1994), The Ruger 10/22, Krause Publications, Iola, WI 54990-0001. A wealth of information on the entire Ruger product line is also presented in R. L. Wilson’s Ruger and His Guns (Simon & Schuster, 1996). These books are required reading for collectors and others who are serious about the Ruger 10/22.

Ruger 10/22 fans will find a wealth of information in the books by Workman and Wilson.

There are also a number of variants that were prepared specifically for a particular distributor but which were never Ruger catalog items. One of these has a 22-inch stainless steel barrel and checkered hardwood stock. This variant was marketed by Lipsey, a large firearms distributor in Baton Rouge, Louisiana, through a large number of Wal-Mart stores. On some Internet chat rooms, owners refer to it as the Wal-Mart version of the 10/22. As this is being written, several distributors are marketing versions of the Ruger 10/22 that are finished completely in camouflage patterns. Over the years, there have been other short runs of 10/22s produced that had special characteristics. For example, the 40th Anniversary 10/22 produced in 2004 had a large medallion embedded in the right hand side of the buttstock to commemorate the event. A brother-in-law of mine has a Ruger 10/22 with stainless steel barrel and laminated stock that was marketed with a 4X scope and sling with the Ruger logo. Apparently, this package was offered through a large chain of stores but never appeared as a catalog item. As mentioned earlier, the Ruger 10/22 has appeared in many forms over the last half century.

THE RUGER 10/22 CARBINE AND DELUXE SPORTER

The original Ruger 10/22, the Carbine, was offered with a walnut stock and 18.5-inch blue steel barrel. Over the many years of its production, it has been produced in many other forms that include some having stainless steel barrels and laminated, composite or hardwood stocks. One of the most attractive versions is known as the 10/22 International, which has a full-length Mannlicher-style stock. A personal favorite is the version designated as the 10/22 DSP, known as the Deluxe Sporter version. It has the same length barrel as the Carbine, but has a checkered walnut stock with sling swivels installed. It is not surprising that over the 50 years since it was introduced, the 10/22 has undergone many changes, most of which are minor.

View a text version of this table

This version of the Ruger 10/22 was distributed by Lipsey and widely available through Wal-Mart stores. It has a 22-inch stainless steel barrel and a checkered hardwood stock.

At one time, the Ruger 10/22 Carbine was available with a stainless steel barrel and a laminated stock.

With a good scope attached, the 10/22 Carbine is a versatile rimfire.

The checkered walnut stock helps make the Ruger 10/22 Deluxe Sporter a handsome rifle.

Although the Ruger 10/22 broke with tradition in many areas, perhaps most unique was the fact that it uses a rotary magazine holding 10 rounds in .22 LR (nine rounds in .22 WMR) that is completely enclosed in the action. This results in a clean profile, with a magazine that does not protrude from the bottom of the action precisely where it is natural to hold the rifle as it is being carried in one hand. Even though this cartridge reservoir is novel, this is not sufficient to explain why the 10/22 is held in such high esteem. No, it is the Ruger rotary magazine, which enables it to rank among the most reliable .22 autoloaders, that has endeared it to many shooters. The action of the 10/22 is legendary for long life and reliability, and the 10/22 also has an excellent reputation for accuracy among rifles of this type. These attributes are responsible for many 10/22s being found in remote areas where the owners need a reliable rifle for pest control and small game hunting.

One of the hallmarks of the Ruger 10/22 has always been the reliable 10-shot rotary magazine. Shown here is the magazine made of clear plastic that comes with the Compact model.

The rotary magazine does not protrude from the bottom of the action. Note, however, that the new style of magazine release does protrude from the bottom of the action.

An adjustable folding rear sight is used on most versions of the Ruger 10/22.

The Ruger 10/22 has always featured a receiver made of an aluminum alloy. Although this is true of the 10/22 in .22 LR, those in .22 WMR have steel receivers. If you fire both the .22 LR and the .22 WMR rifles, you will quickly see that they are in some respects quite different rifles. Because of this, they will be considered separately.

The front sight on the Ruger 10/22 Carbine is a bead on a post that is held in a dovetail groove.

For many years, the Ruger scope base accommodated mounts that clamp in the grooves along the sides.

In the last few years, Ruger has supplied a scope base that not only has grooves along the edges but also transverse grooves that accept Weaver-type rings.

Although the 10/22 comes with excellent open sights, the accuracy of any rifle is easier to demonstrate by adding a scope. However, because the receiver has a slightly rounded profile, it is not possible to have the commonly used groves milled in it to accommodate scope mounts. Instead, the top of the receiver has four dummy screws that fill the holes where the screws that attach a scope rail can be fastened.

For many years, the standard scope rail had grooves along the sides that resemble those milled into the receivers of most rimfire rifles. Beginning in 2004, all versions of the Ruger 10/22 were shipped with a scope rail that not only has grooves along the sides to attach clamp on mounts, but also the base has transverse grooves that enable the enormously popular Weaver-type scope rings to be attached. The new scope rail thus increases the options that are available with regard to the types of mounts that can be used to attach a scope to a Ruger 10/22. The steel receiver of the 10/22 in .22 WMR caliber has raised sections that have milled into them the curved notches that are like those found on the centerfire Ruger rifles. Thus, mounting a scope on a 10/22 magnums is an entirely different situation from that of the .22 LR version.

The Ruger 10/22 Magnum has scope bases that are part of the receiver to which Ruger rings can clamp.

Introduced in 2004, the Ruger 10/22 Rifle has many of the features of the Carbine but has a more slender, better shaped stock.

THE RUGER 10/22 RIFLE

Introduced in 2004 but discontinued as a factory version in 2006 and available now only as a dealer exclusive from Williams Shooters Supply, the Ruger 10/22 Rifle represents a sort of combination of the Deluxe Sporter and Carbine versions but with some unique features.

The Ruger 10/22 Rifle has a rounded end on the forearm and has no barrel band.

First, the Rifle has a 20-inch barrel rather than the shorter 18.5-inch barrel used on the Carbine and Deluxe Sporter. Like the Carbine and Deluxe Sporter versions, the barrel of the Rifle is fitted with open sights. Second, the stock is slimmer than those used on either the Carbine or Sporter. One of the esthetic deficiencies of the 10/22 Carbine has always been that the stock is rather fat in cross section. This is necessitated by the enclosure of the rotary magazine, which is approximately twice as wide as a magazine that holds single-stacked rimfire cartridges. However, the stock of the Carbine is fairly thick throughout its entire length. On the Rifle version, the stock is slimmer and especially so in the areas of the grip and the forearm. With its longer barrel and slim stock, we developed a love at first sight relationship with the 10/22 Rifle. It would be some time before we owned one, but it was worth the wait. Unfortunately, the 10/22 Rifle was offered only with a hardwood stock and a blued steel barrel. It would be very attractive with a checkered walnut stock.

The butt plate on the Ruger 10/22 Rifle is flat and checkered, rather than curved and slick as on the Carbine.

Since it was introduced in 1996, the Ruger 10/22 Target has developed an excellent reputation as a highly accurate rimfire.

THE RUGER 10/22 TARGET

Rimfire shooting sports, such as benchrest and silhouette competition, demand a rifle that is more accurate than the factory-produced Ruger 10/22 Carbine. Although many shooters modify their carbines (the primary reason for this book), Ruger decided to offer a more capable rifle, and the 10/22 Target was the result. It features a 0.920-inch diameter, hammer-forged barrel, a heavy target-style stock, and better trigger action than that of the 10/22 Carbine. These attributes go a long way toward removing the necessity for adding aftermarket parts for many shooters.

The Ruger 10/22 Target has a wide forearm, and sling swivels are provided.

Although one might never actually think of the Ruger 10/22 Target as beautiful, it is impressive. With a 20-inch hammer-forged barrel measuring almost an inch in diameter and an attractive brown laminated stock, the 10/22 Target weighs 7.5 pounds. It comes with no sights attached because this rifle begs to have a scope attached and to be challenged. Target versions of the 10/22 are available with either blue or stainless steel barrels, and both come with target type crowns. Functioning of the 10/22 Target is identical to that of the other forms of the 10/22.

A target crown is used on the 0.920-inch hammer-forged barrel of the Ruger 10/22 Target.

The rubber butt plate on the Ruger 10/22 Target prevents slipping when shooting from a bench.

In late 2005, Ruger introduced the 10/22 Compact Rifle (right), which is a scaled down version of the 10/22 Rifle (left).

THE RUGER 10/22 COMPACT RIFLE

Recognizing that in many situations a rifle of smaller dimensions is appropriate, Ruger produced a compact rifle in September 2005 by scaling down the Ruger 10/22. The resulting version, known as the 10/22 Compact, features a blued barrel measuring 16.5 inches in length and a shortened hardwood stock that gives a 12.5-inch length of pull. The stock has a regular flat butt plate, and gone is the barrel band. In many ways, the Compact resembles the Rifle version, except for having a shorter stock and barrel.

The front sight of the 10/22 Compact Rifle has a fiber optic insert along the top.

Sights on the Compact consist of a front sight on a low ramp and a blade rear sight. Along the top of the front sight is a fiber optic insert, and the rear sight has fiber optic inserts on either side of the notch. As with all current 10/22 versions, Ruger supplies a scope base with the Compact that can accommodate either tip-off or Weaver-type rings.

The rear sight on the 10/22 Compact Rifle utilizes a fiber optic insert that appears to be a green dot on either side of the notch.

In 2004 Ruger produced 10-shot magazines made of clear plastic for the 10/22. These magazines have a red rotor. It is the clear magazine that is standard on the Compact model. Altogether, the 10/22 Compact is a handy, sturdy autoloader that travels well. It is convenient not only for shooters of small stature, but also anyone who wants a very compact rimfire rifle, and that covers a lot of territory.

THE RUGER 10/22 TACTICAL

The 10/22 Tactical version comes in two variants, one with a Hogue OverMolded stock, heavy barrel and bipod (pictured); and the other with a polymer stock, standard weight barrel and flash suppressor. (Photo courtesy of Ruger)

Rifles that have a tactical look are enormously popular. There are many aftermarket products available to give the Ruger 10/22 that type of appearance. As interest in the appearance of firearms changed, it was only natural that Ruger would introduce a factory version of the 10/22 designated as the Tactical model, available in two versions, both of which have 16.12-inch barrels. The sporter version, which weighs only 4.30 pounds, has a flash suppressor, incorporated Picatinny-style rail, blued metal, and a black synthetic stock with a barrel band. The target version weighs 6.88 pounds and has a bipod mounted on a Hogue OverMolded stock.

It should be obvious that large distributors want to market something special and exclusively theirs. As a result, there are many 10/22s available configured in tactical versions designed by these distributors.

THE RUGER 10/22 TAKEDOWN

The Takedown model is designed to disassemble quickly into two parts. (Photo courtesy of Ruger)

With the increase in interest in various types of outdoor activities and the desire to have a firearm available, Ruger introduced the 10/22 Takedown® in 2012. This model can easily be disassembled into two sections by simply moving a recessed locking lever forward and turning the barrel section counterclockwise about one-fourth turn. The stock and action can then be separated from the barrel and forearm. A curved butt plate and fore end with a barrel band make the Takedown model resemble the Carbine.

The curved butt plate on the Takedown model is an integral part of the polymer stock.

After opening the action, the Takedown is easily disassembled by pushing the recessed locking lever forward and twisting the rifle.

Two factory versions of the Takedown are available. One has a stainless steel barrel measuring 18.5 inches in length and bright aluminum receiver mounted on a black polymer stock and forearm. The other version has a blue barrel measuring 16.62 inches in length attached to a blue receiver and black polymer stock. This version has a threaded muzzle for attaching a flash suppressor. Both versions are equipped with open sights in keeping with the idea of a complete, portable rifle. Each Takedown rifle comes with a black, backpack-style carrying bag that holds the two sections of the rifle in separate compartments.

The Takedown model comes with a backpack for transporting the disassembled firearm.

The Takedown version has become extremely popular, which has resulted in it being available in many forms from various distributors. Lipsey’s, Davidson’s, Sports South, and AccuSport each have the Takedown in several configurations.

ENHANCING THE RUGER 10/22

Shown are just a few of the aftermarket items available for the Ruger 10/22. This firearm is an industry in itself.

It is unlikely that any machine produced by a factory, even using modern manufacturing techniques, could not be made better in some way. Manufacturers must make decisions based on availability of materials, cost-related issues, and marketability of the end product. A custom shop may not be forced to operate under all of these constraints, and the owner of a Ruger 10/22 certainly does not have to. Almost everything except the receiver housing is replaceable. Moreover, components are available that are designed to exceed the capabilities of the original factory components in many instances. The owner of a Ruger 10/22 can customize his or her rifle to almost any degree desired. As good as the Ruger 10/22 is in factory form, it can be made better. In the following chapters, we describe the performance of factory rifles and others that utilize many of the aftermarket products available for the 10/22. We also describe how you can turn your rifle into an elegant tack-driving machine using aftermarket parts.

With a concern for safety, Ruger supplies a lock with each of their rifles.

The replacement of barrels and stocks on Ruger 10/22s is so common that several companies offer accessory kits that consist of a stock and barrel combination. Stocks range from an elegant sporter type to tactical models with pistol grips, hand guards and folding buttstocks. Laminated stocks are also available in various color combinations. One popular type of aftermarket stock is known as the thumbhole model, and many styles of that type of stock are produced. In general, stocks are produced with barrel channels that are cut to fit either a factory barrel or to fit a heavy barrel having a diameter of 0.920 inch. Stock options for the builder of a custom Ruger 10/22 are discussed in Chapter 7.

When it comes to barrels for the Ruger 10/22, the term smorgasbord comes to mind. Some barrels have contours that match that of the factory Carbine barrel, so they can be used with the factory stock. Probably the most popular style of aftermarket barrel is that having no taper but rather having a uniform diameter of 0.920 inch. Within this general type, the buyer can choose from a blue finish or stainless steel. Another type of barrel, referred to as a running bore model, has the same configuration as the factory barrel for most of its length but for the last four inches or so the diameter is increased to 0.920 inch. This allows the use of the factory stock or a stock that has a barrel channel of the same size. Finally, there are several barrels available that have an outside diameter of 0.920 inch, but which have an inner sleeve made of steel encased in a sleeve made of aluminum or a carbon fiber composite. These barrels are light in weight, but they can be used with a stock that is designed for use with a heavy barrel. General characteristics of barrels are presented in Chapter 8, although specific models and their performance are discussed in Chapter 11.

Because of the vast array of items produced for the Ruger 10/22, not all of the aftermarket products available could possibly be tested or even shown in this book. Those that are described are certainly representative of most of the accessories that are available, but it is not a complete list. Before you embark on customizing your 10/22, study the catalogs and websites of the manufacturers listed in Chapter 13. You may find that there are many more options available than you ever imagined even after studying this book. It is indeed a very large market. After all, the Ruger 10/22 is that kind of machine, and as you will see it would be very difficult to outgrow this little rifle, because it is capable of a lot of growth itself. The remainder of this book is devoted to helping you make decisions on aftermarket items and getting the most out of your Ruger 10/22.

CHAPTER 2

DESIGN CHARACTERISTICS AND CONCERNS

Before setting out to create your ultimate Ruger 10/22, it is desirable to understand some of the basic aspects of firearm design. Some of these features and characteristics are related to the type of aftermarket items to be installed. For instance, replacing the factory firing pin with one made of titanium decreases the lock time. As a result, replacing some parts of a rifle may alter the design characteristics of the rifle, which may be desirable or, if not done properly, undesirable. Consequently, before discussing various aspects of customizing the 10/22, we will discuss some of the relevant aspects of firearm design and function.

Please note that replacing almost any part on a Ruger 10/22 with an aftermarket part will invalidate the factory warranty! Please note also that returning a rifle that contains aftermarket parts to Ruger for service or repair will result in the aftermarket parts being replaced by factory parts! The rifle will be restored to original condition whether you want it to be or not. For example, that special hammer and sear that you installed will be replaced by gritty, rough factory parts. Make sure that any rifle you return to the factory contains only factory parts, not your treasured aftermarket goodies. Keep in mind that the authors are not professional gunsmiths and the information presented is for educational purposes only. Anyone other than a professional who modifies any firearm does so at his or her own risk.

This .22 LR cartridge is resting on the face of a bolt from a Ruger 10/22. Note how the recess in the bolt face accommodates the cartridge rim.

The dial on this caliper has been set to read zero when an empty .222 Remington case is placed between the jaws.

With a .22 LR cartridge inserted in the mouth of the .222 Remington case, the dial reads 0.044 inch, the thickness of the .22 LR rim.

HEADSPACE

When a cartridge is placed in a chamber, there must be some clearance, not only along the chamber walls but also between the end of the barrel and the bolt face. Rimfire rifles have a cut out area on the face of the bolt where the head of the cartridge rests when it is in the chamber. When the bolt is fully closed, the cut out area has sufficient room for the cartridge head in addition to a small amount of clearance. On semiautomatic rifles, the bolt goes forward until it makes contact with the rear end of the barrel, and the head of the cartridge rests in the cut out area in the face of the bolt. In a rimfire rifle, the distance between the back of the recess in the bolt face and the rear end of the barrel is referred to as the headspace.

Cartridges in .22 LR caliber normally have rims that are about 0.037-0.042 inch in thickness. Because the bolt face in the Ruger 10/22 rests against the rear end of the barrel, the recess in the bolt face must allow for rims that are at least 0.042 inch, with a couple of thousandths of clearance. In most .22 LR rimfire rifles, the headspace is about 0.043-0.045 inch. If the headspace is too small, closing the bolt causes some deformation of the case head that could cause the cartridge to fire if the bolt action is violent, as it is in the case of an autoloading rifle. If the headspace is somewhat too large, firing the cartridge can cause the case head to expand to fill up the empty space. In such cases, the head of the fired case can show noticeable rounding or ballooning. If the headspace measures about 0.003-0.004 inch too large, the firing pin can move the cartridge forward in the chamber, which will result in a dent that is too shallow in the case rim. Misfires can result in such instances.

If you have any question about the headspace in any rifle, have the rifle examined by a qualified gunsmith who has the gauges to make accurate measurements.

Most aftermarket barrels for the Ruger 10/22 are produced so that, when they are placed correctly in the receiver, the bolt simply butts against the rear of the barrel extension. When a barrel is removed from a Ruger 10/22 it is easy to see the slight discoloration or roughness where the bolt has repeatedly struck the barrel. Headspace is controlled by the depth of the recess in the bolt face so there is little likelihood that it will be incorrect. This is not the case when the barrel is changed with a bolt action rifle such as the Ruger 77/22. In the case of a bolt action rifle, the bolt locks in place against the receiver in a specific location regardless of where the end of the barrel is located. Therefore, it is essential that the headspace be controlled by how far the barrel extends back into the action. Rifle barrels have a step where the barrel shank has been turned to smaller diameter, and this step fits against the face of the receiver. If the barrel shank protrudes too far into the action, the bolt may not close. This condition can be corrected by placing thin spacers around the barrel shank so that it will not extend too far back in the receiver.

The barrel tenon or shank shows the effect of being struck by the bolt during firing.

This fine Green Mountain barrel has a shank that determines how far the barrel protrudes into the receiver.

If the barrel does not protrude far enough into the