March 6, 2013

Making The Ruger 10/22 Team Challenge Conversion

As more people use these guns, you’ll be called upon to make drop-in parts drop in and solve other difficulties associated with this upgrade.

Because of the inherent accuracy and reliability of the Ruger 10/22 autoloading rifle, it has become the overriding favorite of gunsmiths who are building guns for Sportsman Team Challenge competitions, events which include two rifle legs. In fact, the competition has spawned a healthy aftermarket industry for all sorts of 10/22 modifications that can make the 10/22 even more accurate and reliable.

One of the most common changes made to 10/22s are adding aftermarket barrels. There are about five or six styles of aftermarket barrels available for this rifle, and all claim to be a drop-in fit. The aftermarket barrels I have examined, most of which had match-grade chambers cut into them, were well made, and they usually price out at around $275 to $300 retail.

The positive effects of adding a match-grade barrel and shooting match-grade .22 ammunition in a 10/22 can be astounding, as a recent conversion I performed showed.

First Step

A customer who owned a stock 10/22 rifle wanted a conversion done, and he wanted to use a Volquartsen heavy stainless steel barrel with integral muzzle compensator. The compensator has eight rows of four 17/64-inch diameter holes to vent powder gases. This barrel measures 203/16 inches in length, including the muzzle brake and has an advertised diameter of 0.926 inch from muzzle to chamber end without any taper. The Volquartsen barrel I received for this rifle miked 0.928 inch at the rear and 0.927 inch at the front diameter of the compensator, very close to the advertised dimensions.

To install one of these drop-ins, remove the two screws on the barrel block and take off the factory barrel. Measure the length of the factory barrel shank that goes into the receiver from the rear face to the barbe about 0.750 inches, plus or minus 0.005 inch. Measure the length of the barrel shank on the new barrel to see that it is within this tolerance range. The shank diameter of the factory barrel runs around 11/16 inch or 0.6875. The new barrel should be as near this dimension as possible, unless the original barrel was sloppily fit. The barrel shank hole in the receiver should be inspected for burrs and any high spots that will appear shiny. Try the new barrel in the receiver receptacle for fit.

Gunsmithing the Rifle, Chapter 15

Courtesy, American Gunsmith Magazine

This is a Team Challenge 10/22 containing many of the modifications noted in the text below, including a compensated barrel, trigger job, composite thumbhole stock, and a heavy target barrel and special chamber. The rifle shown also has a special set of blocks to get the shooter’s eye in line with a totally erect head position on the stock.

The shoulder at the front of the receiver acts as a barrel support shelf and may need to be relieved somewhat so that the new barrel will clear. Most all of these barrels are made so that the fit will be tight, almost a press fit. There is also one manufacturer who actually threads the receiver hole after line boring and also threads the barrel shank for fitting. In the event that the barrel shank will not enter the receiver, there are several options for fitting. If you have access to a lathe, the barrel can be set up in it and the tenon diameter either turned to fit or polished with emery cloth as it turns to achieve a tight fit. Running an 11/16-inch reamer into the receiver hole by hand or at a very slow drill press speed will true up the receptacle if it appears to be misshapen. The idea here is to not remove any more material than necessary to have a tight fit.

The replacement barrel I used weighed in at 3 pounds, twice the weight of the factory barrel with a diameter of 0.927 inches. To fit the barrel in the factory stock, you will need to relieve the barrel channel to accept the new barrel. Also, Volquartsen recommends that two 1-inch-wide epoxy barrel support pads be glassed into the barrel channel to help support this heavy barrel. Install one pad in front of the action screw and the other pad at the forend tip. (However, because I used a Volquartsen black composite thumbhole replacement stock, these pads were already built into the forearm. Once the new barrel was mounted on the receiver, the barreled action actually did drop in and fit properly, something you don’t always encounter with so-called drop-in-fit items.

Gunsmithing the Rifle, Chapter 15

Courtesy, American Gunsmith Magazine

Some Volquartsen heavy stainless-steel barrels come with integral muzzle compensators, which have eight rows of four 17/64-inch diameter holes to vent powder gases.

The customer liked the idea of having the receiver match the color of the stainless-steel barrel, so the receiver, trigger guard, and all other parts previously blued or anodized were bead blasted with fine aluminum-oxide grit beads. The blasted parts were then coated with a clear-matte bake on lacquer finish and then baked at 350 degrees for 30 minutes.

Scope Base Installation

This job also called for the use of a cantilever scope base manufactured by Weigand Combat Handguns, Inc. This cantilever base requires that three holes be drilled and tapped into the barrel for placement so that the rear of the base extends back over the receiver. This base was designed to be used on heavy bull barrels of the style and diameter used for this conversion. Although this mount was said to fit barrels up to 0.960 inches in diameter, the radius cut into the bottom of this mount did not fit the barrel contour very well at all. To fix it, I set up a 15/16-inch ball-end mill in my mill and milled the radius of the base to a contour which matched the barrel radius more closely, which also resulted in reducing the gap between the rear of the base and the receiver, in this case 0.014 inches. This was exactly the gap between the upper inside face of the scope mount and the top of the receiver.

I then drilled two clearance holes into the rear of the mount so they would line up with the two front holes used for base mounting in the receiver. The cantilever mount would now act as a bridge connecting the barrel and receiver.

Gunsmithing the Rifle, Chapter 15

Courtesy, American Gunsmith Magazine

The Ruger 10/22’s receiver and bolt parts fit together in this order.

The major complaint I had with this mount is the lack of critical instructions concerning screw-thread diameter. There are three base mount screws included with this mount, but nothing to designate what the screw size is. If I hadn’t routinely checked the screw threads, I might have assumed they were #6-48 threads, common to most scope-base mounting holes, and drilled and tapped the holes in the barrel for that thread.

As it turned out, the mounting screws are #6-40 threads with an 82-degree tapered head, which requires the use of a hex wrench. Instead of using the supplied #6-40 screws, I chose to go with #6-48 screws for mounting the cantilever base to the barrel. My reason: The two front base holes in the receiver are #6-48 threads, and these two holes attach the rear of the base to the receiver. If had used both the #6-40 and #6-48 threaded screws, it would be confusing to the owner or another gunsmith who may happen to work on this firearm in the future, especially if the screws were mixed up on a work bench.

To attach the base, drill three holes in the barrel at the proper spacing using a sight drilling jig. Then tap these three holes to #6-48 and cut three stainless-steel screws to length and fit them in place. Set up the barreled action in a drill-press vise and level the top of the base. Chuck up a No. 11 bell-type center drill in place and then remove the base, leaving the center drill lined up over one of the rear scope base holes. Double-check to make sure the alignment was correct, then put the cantilever base back on the barrel and screwed it into place without moving the setup. Use the center drill to spot drill the base for one of the through-holes. Remove the base and center the center drill over the other rear receiver hole. Attach the base once again using the same procedure.

Then, remove the base from the receiver and drill two 9/64-inch through-holes in the base. Use a step drill to cut the screw head clearance down to the proper depth in the base. (A center drill should be used to spot drill these two holes because it is a stiff short drill that doesn’t walk off location. This may seem like a lot of fooling around to get this base centered over the tapped holes now in the receiver, but I found out a long time ago that if you take the time when you first do a job, you won’t have to spend a lot more time trying to fix a catastrophe.)

Gunsmithing the Rifle, Chapter 15

Courtesy, American Gunsmith Magazine

The trigger group includes the following items: 1 hammer pin, 2 ejector pin, 3 trigger pivot pin, and 4 magazine release pivot pin.

Wrapping Up

This mount was designed to be used with Weaver-style scope rings, so I had my pick of rings. I chose Burris Z-rings in safari grade to hold the Burris 6 to 18 power variable scope over the bore of this conversion. These are steel scope rings that have two V notches cut into the bottom sides of the rings so that they will fit on Weaver style bases. As purchased, they would not fit on the Weigand base, so I set up each ring in my milling vise, leveled it, and removed a 0.050 inch from the bottom side of each V notch so that the rings would slip onto the base.

Once everything was together, it was time to compare the trigger pull after I had worked on the gun to what I had begun with. Before I had begun work on the gun, I noted its trigger pull was 51/2 pounds before disassembly, and one of my goals was to smooth it out and reduce it to 31/2 pounds. After installing some new trigger parts and polishing others, I was able to make the trigger let off and break cleanly and safely at 21/4 pounds on average.

All the additions, including the scope and rings, made the rifle scale out at 81/4 pounds, but its performance is worth the extra weight, the customer told me. His group sizes have been cut in half, and he has a distinctive, attractive firearm to boot.