(Editor’s Note: Ed Harris is back! He recently sent me a big archive of his older articles, and there are some real gems in there. I’ll be featuring one of these treasures every other Friday! Today Ed talks about rebarreling a .22 rifle to turn it into a budget tackdriver. Some of you may remember that I love playing with .22 rifles, and you can bet I was taking notes as I read this!)
RE-BARREL YOUR 22 BOLT ACTION AND… Make an accurate smallbore silhouette or squirrel rifle!
by C.E. ‘Ed’ Harris (Rev. 3-1-94)
The idea of an accurate, .22 rimfire rifle weighing 7-1/2 or 8 lbs. with scope, having the same sleek good looks and steady handling as my center-fire varmint rifles was very appealing. We could have used any quality .22 bolt-action for this project, but my Ruger M77/.22 rifle was a natural choice. It was available, and while serviceable, it was an ordinary grouper. Arlington, VA gunsmith Jim Coleman suggested a heavier barrel with SAAMI-dimensioned “Match-type” chamber, and pillar bedding and minor tuning up. The result is very satisfying, and more useful than the original rifle.
My customized Ruger is highly accurate, being capable of 3/4″ 10-shot 50-yard groups with good high velocity and approaching 1/2″ with the best match ammunition. (See the article “Getting the Most from Your .22 Rimfire” in the 1992 Gun Digest for more details). It weighs 7-1/2 lbs. with a hunting scope, or 8 lbs. with my 10X Unertl, handy enough for field carry when after squirrels or close-range woodchucks. It is now the most-used rifle in my gun rack. I am truly surprised that Ruger still hasn’t offered a heavier-barrel M77/.22 with match chamber.
Rebarreling a sporter with a heavier barrel can be done economically if you can find a good used target rifle barrel. Used .22 target rifle barrels with bright, sharp bores, in serviceable condition, can be set back and rechambered successfully. These can often be found at gun shows for $10-40, depending upon local supply and demand, but some luck is involved.
If you know a gunsmith who rebarrels rimfire target rifles, ask him to save you a used Remington 40X, Winchester 52, BSA-Martini or Anschutz barrel. Even if it has been shot a lot, when cleaned up, carefully inspected, set back, rechambered to a SAAMI-dimensioned “match” chamber, and cut to a handy length, a used target rifle barrel will yield a stiff, accurate, 22-24″ steady-holding sporter barrel which will group well.
Setting back the typical 26-28″ target barrel to 22-24″ barrel will remove all of a worn or eroded breech, and leaves plenty enough to cut and recrown the muzzle, giving a handy field gun which is heavy enough for proper balance. However, if you want a flyweight tack driver, this can also be done. My buddy Nick Croyle put a piece of used Hart target barrel on his M77/.22 and had Jim Coleman turn it to the proportions of a buggy whip, and that 5-1/4-lb. rifle with 19″ barrel will shoot 1/2″ , ten- shot bugholes at 50 yards with Eley Tenex, his squirrel load!
Rebarreling .22 rimfire bolt-actions with threaded barrels such as the Kimber 82, Remington 40X, or Winchester 52 are done much the same as a center-fire rifle, except that excessive tightening of the barrel must be avoided. Otherwise the smaller shank on the softer rimfire barrel (typically 1137 steel of Rockwell B80-90 hardness) may become constricted at the root of the thread where the barrel shoulder stops against the receiver.
For non-threaded barrels, such as Anschutz, the barrel pins must be removed to free the old barrel. The ends of the pins are often polished before bluing cheap rifles, and may be hard to see. They are obvious on Anschutz and other European match rifles.
The Ruger M77/.22 barrel is the easiest to remove, and is accomplished by removing two cap screws which hold the barrel retainer. The Ruger M77/.22 barrel is retained in the receiver by a V-block shaped retainer held by two cap screws. The retainer engages a 45 degree cut in the underside of the barrel. You can copy the old barrel fairly easily. The retainer slot can be rough cut with hacksaw and filed to final dimensions or machined in a milling machine or using the milling attachment in the lathe. The Ruger 10/.22 autoloader barrel is attached similarly, but requires careful attention to the chamber for safety reasons.
The barrel shank at the breech of non-threaded replacement barrels should be turned one half a thousandth of an inch (0.0005″) less than the diameter of the barrel hole, so that it is a snug fit, without having to force it home. You should be able to insert the barrel by hand with slight resistance, pick up the action with the barrel in place, and shake it without loosening. A “forced fit” must be avoided because it may cause a constriction near the chamber which will hurt accuracy.
The looser fit of .002″ less than the barrel hole, as found on factory Ruger barrels is normally satisfactory, but may influence accuracy if heavy stock fore-end pressure, common as the rifles from the factory) exerts pressure against the barrel. For that reason we prefer free floated barrels.
Nearly all .22 rimfire barrels require clearance cuts for the extractor and cartridge supports. These can be cut by hand with a hacksaw and finished with small files, but it is best if they are done in a milling machine, or using with a milling attachment in a lathe. Extractors and cartridge supports are semi-circular in shape, and factory clearance cuts are radiused, not straight as a file cut would be. These cuts are located by coating the extractor and cartridge support with lipstick or Prussian blue, and gently inserting the bolt and closing it only enough to “mark” the points of contact to show where the cuts are to be made, which then copy the factory barrel.
Best accuracy in bolt actions with a variety of ammunition requires the use of the .22 Long Rifle SAAMI-dimensioned “Match” chamber. Testing indicates that the “Match” chamber gives a truly dramatic improvement in grouping compared to the common “sporting” chamber. To prove to ourselves we took two match-chambered barrels of established accuracy and reamed them to the normal “sporting” chamber, with no other change. The average extreme spread of fifty consecutive 10-shot groups at 50 yards, firing ten groups each with five different ammunitions, actually doubled when a match chamber was enlarged with the sporting reamer!
Semi-auto .22 rifles can also be rebarreled successfully, but it is dangerous to use the tight SAAMI-dimensioned “Match” chamber in an autoloader, because it WILL slam-fire and blow case heads off. However, the typical “Sporting” .22 LR chamber is too large in diameter, and also too long for best accuracy. In an autoloader the “Winchester 52D-Type” chamber (discussed in my article “Building an Accurate .22 Autoloader” in the 1993 Gun Digest) is what you should use. If you plan to do all types of.22 rimfires, boltguns, autoloaders and handguns and only want to buy one reamer, get the “Winchester 52D-Type.” JGS Precision, 1141 South Sumner Road, Coos Bay, OR 97420 can provide these.
If the barrel is to be pinned permanently in place, rather than using a Ruger-type retainer, first cement it in place with “service removable” (Blue #241) Loctite prior to function test firing to ensure the extractor slots line up and do not bind on the bolt. This permits brief test firing and removal for adjustments, if needed. Once feeding and extraction are proven reliable, use the existing barrel pin holes in the receiver as guides to drill and ream new holes for somewhat larger straight pins, or tapered pins to secure the barrel.
The Ruger M77/.22 magazine feeds rounds almost straight into the chamber and requires only minimal breaking of sharp edges on the chamber entrance. A crowning ball with 320 grit abrasive works well to just remove the wire edge. On other makes of rifles which tend to shave lead, chamfering of the chamber entrance must not be over-done, lest it cause bulged case heads, which may cause burst cases, risking personal injury!
I have have found that almost all .22 sporters group more consistently when the barrel is free floated. It is also necessary to ensure that the receiver is evenly supported. If the rifle shoots tight, round groups without significant change in point of impact as the barrel heats and after taking the action in and out of the stock several times, the bedding should not be changed. Otherwise, “pillar bed” the action exactly as done for a center-fire rifle.
This is done by machining through the stock screw holes with a 3/8″ drill or end mill, and fitting brass or aluminum bushings which are epoxied in place. Using metal bushings avoid the possibility of shrinkage voids which may occur when trying to “pillar” the guard screw holes with bedding compound. Solid pillar bedding positively prevents wood compression when the screws are drawn snug, holds the action in alignment without bending or twisting, and ensures free clearance of the action screws in the stock so they work in tension, as intended, rather than applying a shear force to the receiver.
Scope bases must be firmly attached. We prefer either Ruger rings on the M77/.22, or Unertl Posa-Mount bases with Unertl external adjustment scopes. Scope rings for internal adjustment scopes should be lapped after mounting on the receiver, to correct for any machining irregularities in the scope bases or rifle receiver. This ensures that the scope tube is not bent or misaligned when the mounts are drawn up snug.
Lapping of scope rings is done by turning a bar of round mild steel, brass or aluminum to .998″ diameter on centers and about 10″ long. The lower halves of the scope rings are firmly attached to the bases in the normal manner, then lapped with 240 grit to obtain at least 2/3 surface contact.
As for choosing the scope itself, years of experience in the Virginia Blue Ridge on squirrels has proven the value of a 6X scope on small game rifle. For a hunting rifle we suggest having the parallax corrected for 50 yards, but smallbore silhouette shooters should have it optimized for the 75m turkey, which is the most difficult target. A higher magnification is OK for a pure silhouette rifle, but is harder than a 6X to hold steadily in a field position when you have been climbing ridges, is less bright on dark days or in heavy foliage, and usually has too small a field of view for tracking a fast-moving bushytail!
For hunting a 2-minute dot at the center of the crosshairs provides a highly visible aiming point, in poor light, but one which does not obscure small game targets at realistic ranges. An additional 1/2 minute dot centered 7″ below the crosshairs provides correct 100-yard holdover for standard velocity target, or sub-sonic hollow-point hunting ammunition. Set the second dot at 6″ if you favor high speed ammunition. Dick Thomas at Premier reticles can provide this service on most scopes for a reasonable charge, with about 3-6 weeks turnaround time. (Editor’s Note: Since this article was written, Premier Reticles has stopped offering aftermarket reticle services, having transitioned to manufacturing scopes exclusively a few years ago – see my SHOT show recap for a discussion of their new product line. At this moment the only place I know that can provide an aftermarket reticle such as Ed describes is the T.K. Lee Company in Alabama.)
Many people have wanted the address of Jim Coleman, who built my rifles, I guess because they have seen the copious volumes of accuracy data featured in American Rifleman and the Gun Digest. I am happy to do this, but point out there are plenty of competent gunsmiths who can do this work. I am pleased with what Jim did for me, but I have no financial stake in this whatever.
James C. Coleman can be reached at Coleman’s Custom Repair, 4035 North 20th Rd., Arlington, VA 22207, telephone ( 703) 528-4486. It is best to query him by phone first to see what his current work load is, as he is a one-man shop.
Now that you have some ideas on how to make a really serious rimfire, we better warn those bushytails to jump fast and stay hidden!
- Posted by Grant Cunningham
- On February 10, 2012