By Nathan Foster
Although I have a passion for hunting big game and studying centrefire cartridges, one area of research that I have not included in the book, Hunting Cartridges of the World, is my experiences with the .22 rimfire cartridge and rimfire rifles.
Although the .22lr is used for practice, plinking, pest control and varminting, in NewZealand, the .22lr is relied on as a working tool for the hunting of possums for profit.
The Brushtail possum is a small omnivorus nocturnal marsupial, about the size of a house cat, that was introduced into NZ from Australia by early settlers. In NZ's temperate climate Possum numbers soon climbed to plague proportions. The possum is currently classed in NZ as a pest however it is also viewed as a valuable export earner. Possum skins are used to make high fashion fur garments while another market uses the plucked fur blended with merino sheep wool to produce extremely fine, smooth textured textiles with incredible thermal properties.
Methods for hunting possums include trapping, poisoning and shooting. The possum is a tough tenacious creature and although cartridges such as the .22 Magnum, .17 HMR and 12 guage shotgun are ideal, the .22lr is by far the most economical possum hunting cartridge. There are several brands of .22 calibre rifles capable of producing outstanding accuracy for shooting possums, especially for skin hunting which necessitates head shots (body shots are OK when plucking). Unfortunately, some of the better brands of accurate bolt action .22's are slow to reload in the dark and have low capacity magazines.
One of the greatest possum hunting rifles introduced to NZ has been the Ruger 10/22. This relatively budget built semi auto has the firepower and ruggedness required for NZ's sometimes wet muddy conditions but its design towards the goal of accuracy leaves a lot to be desired. Various customising kits are available for the 10/22 and do aid in the development of a more accurate firearm. Where money allows, these drop in solutions are very useful however some modifications can be made without, or as part of the customising process with very good results. For the commercial hunter it must be noted that a custom after market heavy barrel is not desirable as he or she will also be carrying the weight of a mounted spotlight and back packed 12 volt battery. That said, the commercial hunter needs a rifle that is accurate with a wide variety of ammunition in order to be able to utilise cheap ammunition deals as well as subsonic and hyper velocity ammunition depending on individual hunting situations. The commercial possum hunter will likely use up to a brick of ammunition per week.
So how to go about accurising the standard Ruger 10/22 rifle. The following information is given for those with a basic understanding and previous experience bedding firearms. Firearms bedding theory and bedding techniques are a complex subject. For those with no previous experience who wish to pursue the advice given here, their 10/22 rifle, along with this article should be presented to a competent gunsmith.
Without a doubt, it is paramount that the 10/22 trigger either be lightened and tuned by a gunsmith or replaced with an aftermarket kit. This basic modification along with experimentation of barrel tension by adjusting the single front barrel band will usually result in acceptable accuracy out to 50 yards (around 1" groups) with Winchester Powerpoint and subsonic ammunition.
To enhance accuracy further, some degree of action to stock bedding must be obtained to ensure that after each shot, the action comes to rest at the same point of contact with the stock as it did at the last shot. As bedding potential goes, the 10/22 could not be worse in design. Ideally, a rifle action achieves excellent bedding by using the trigger guard and magazine housing as a giant washer. Bolts through the trigger guard into the underside of the stock enable the action to be clamped down into the stock.
The Ruger 10/22 does not have this capability and like most rimfire rifles is designed for the utmost in economy as most shooters usually will not pay large sums for a .22 calibre rifle.
The front of the action sits on stock material however the trigger guard and magazine housing attach directly to the action with no means of securing the rear of the action to the stock. The single front bolt is partially responsible for holding the action in place while the barrel band acts to lock the barrel in a fixed relationship to the action and stock.
The 10/22 is almost a reverse of centre fire rifle design where ideally, the action is fixed to the woodwork and the barrel free floated. The 10/22 is attached to the stock at the barrel and the front of the action while the rear of the action is left floating. Nevertheless, this is not a new design and a solution to superior bedding can be borrowed from a much earlier rifle.
The last variant of the British Lee Enfield SMLE .303 calibre rifle was the No.4 mkII. The mk II had its trigger mounted on the buttsocket rather on the floor plate assembly for smoother trigger let off, some of these models being issued as sniper rifles. The No.4 mkII design necessitated removing all wood from the rear of the action area. With no facility to secure the rear of the action down onto the woodwork, British enginners designed a tie screw to enable the action to be secured to the stock from the sides.
This method of securing the action to the stock is easily adapted to the 10/22 as holes are already drilled through the Ruger action housing. When dissasembling the 10/22, it will be noted that two cross pins secure the trigger housing to the receiver (action). By removing the rear pin (not the recoil buffer pin at the upper and rear most point of the receiver) and tapping the receiver and trigger housing to accept a threaded bolt. The rear sides of the stock can then be drilled and bolts fitted through, into the receiver and trigger housing for a secure fit.
Tools required for this job are a tap wrench, thread tap, suitable bolts and two washers. The hole diameter used by Ruger is .185" or 4.7mm therefore in countries that use the imperial system, a ¼" UNF thread tap and bolts may be fitted while in metric countries the soft aluminium Ruger metal work easily taps to M6x1mm. When tapping through the action, one should try to tap from one side completely through to avoid cross threading bolts at a later stage.
For asthetic sakes, two button head hex head bolts mounted at each side of the stock tend to be the most visually appealing. Never use stainless steel bolts in the aluminium Ruger receiver as the two alloys will react and over time result in severe corosion. Unfortunately, high vibration during semi auto cycling has the potential to loosen dual opposed cross bolts after a period of time. Nevertheless, when using two cross bolts, the operator must be careful not to over tighten the bolts which will strip the soft aluminium threads very easily. Use plenty of threadlocker compound and tighten bolts up to a firm feel only.
As an alternative to dual cross bolts, for a stronger, more reliable system, a single bolt threaded from one side through to, and out the other side of the action and woodwork and secured with a nut creates a more reliable and practical fit. The operator then has the ability to place greater torque on the bolt which is tightened against the nut rather than the aluminium receiver. This method is superior to dual cross bolting but for some hunters, may lack optimum visual appeal.
For both asthetic appeal as well as practical purposes it pays to counter sink the holes in the woodwork of the stock with an over size drill bit and glue washers in place to spread and increase the grip of the bolts to the stock and metalwork. The washers can be painted black for visual appearances and the counter sunk bolt heads ensure the 10/22 retains ergonomic qualities.
Now that the rear of the action is secured to the stock, the front of the action and barrel can be bedded in a more traditional manner. The front barrel band should be removed before bedding the front of the action. The front of the action can be resin bedded out to a point just forwards of the barrel block. Once this has been done, the barrel channel of the stock can be removed of wood contacting the barrel to eliminate lateral pressures to the barrel.
Due to the fact that the 10/22 barrel is bolted to the receiver via a barrel block rather than screwed into the receiver, the 10/22 barrel cannot be left free floating as its loose fitting allows the barrel to move under vibrational forces. To remedy this, the barrel must be pressure point bedded to create a fixed point of tension for consistant accuracy.
Around ¼" of the barrel at the tip of the stock fore-end should be bedded in resin to produce a concentric point of tension. When setting up the stock for fore-end bedding, a small piece of card should be placed between the underside of the action or barrel block and stock. When the barrel is seated in resin, the card will cause the barrel to sit. Later, when the rifle is re-assembled and the piece of card removed, tightening the action bolt/screw will pull down the action onto its bedding surface and produce tension of the barrel at the fore-end.
A piece of card the thickness of a business card is quite suitable for raising the action to a height great enough to later create suitable forend tension once the resin is set and the card is removed. For those who wish to be absolutely sure, a double thickness of card ensures maximum tension. When re-assembling the finished job, be sure to apply enough tension to the action bolt/ screw to pull the action down onto and flush with its bedding platform. Failure to do this will result in poor groups and add confusion when sighting the rifle in.
The Ruger 10/22 bedded and tie screwed produces good groups from its factory barrel with a wide variety of ammunition out to ranges exceeding 50 yards. Some ammunition brands will produce one hole groups at 50 yards while hyper velocity ammunition such as CCI's excellent Stinger ammunition can be relied on to group well and kill small game quickly out to ranges exceeding 70 yards.
Unfortunately, wood stocked 10/22's do suffer from a wandering zero when pressure point bedded at the barrel forend and then exposed to temperature extremes. When used for continous night shooting, the stock soaks up moisture while the heat of the following day causes the wood to move, altering its pressure against the barrel over the course of a few weeks. For commercial hunters who regularily expose their 10/22 to extreme environmental conditions, the rifle's zero should be checked about once every three weeks. A stout, synthetic after market stock is another solution, suitable for those with a flexible budget. For those who use the 10/22 under more desirable weather conditions, the pressure point bedded 10/22 appears to hold its zero well over time.
Some brands of .22 ammunition may be accurate but not function well in the 10/22 regardless of modifications. Remington subsonic ammunition is one example, this ammunition achieves a relatively poor 800fps in the 10/22 and the low velocity gas flow combined with Remington's choice of powder cause fouling which leads to jamming within a few shots. Therfore comments made about ammunition versatility in the modified 10/22 need to be considered in perspective to such factors.
Not many rimfire rifles will stand up to the abuse that the 10/22 is typically able to handle. Having characteristics much more like a military firearm such as the M1 carbine that the 10/22 was modelled off, the 10/22 will keep performing inspite of mud, rain, dust and temperature extremes. The 10/22 has its faults but is well worth utilising as a basis for a reliable working gun.
Disclaimer/ WARNING: The views and opinions expressed in this article are solely those of the author and are not endorsed by Ruger firearms. Terminal Ballistics research and the author take no responsibility for the use or misuse of any views, opinions or information expressed in this article.
