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April 22nd, 2021
The late Bill Myers was recognized as one of greatest rimfire gunsmiths who ever lived. Myers crafted many match-winning, record-setting rimfire benchrest rigs. Here we feature one of Bill’s most interesting creations — a clamping action that allows a rimfire barrel to be indexed (rotated) around the bore axis.
Bill was a creative thinker, and his own exhaustive testing has convinced him that barrel indexing can enhance accuracy in rimfire benchrest guns. Myers did acknowledge that, particularly with a very good barrel, the advantages of indexing may be subtle, and extensive testing may be required. Nonetheless, Myers believed that indexing could improve rimfire accuracy.
Indexing with the Myers’ Clamping Action
To index the barrel, Myers simply loosens the three clamping-bolts and rotates the barrel in the action. Because there is no thread to pull the barrel in or out, the headspace stays the same no matter how much the barrel is rotated. In other words you can rotate the barrel to any position on the clockface and the headspace remains unchanged.
The Challenge of Barrel Indexing
 With a conventional barrel installation, employing a shoulder with a threaded tenon, it is difficult to index the barrel. Even with a cone breech (photo right) that eliminates the problem of extractor cuts, you’d have to use shims to alter the barrel index position, or otherwise re-set the shoulder each time you screwed the barrel in further.
Clamping Action Allows Barrel to Be Rotated to Any Position
Bill has come up with a masterful solution to barrel indexing. He designed and built his own prototype custom action that clamps the barrel rather than holding it with threads. The front section of the action is sliced lengthways, and then clamped down with three bolts. A special bushing (the gold-color piece in photos) fits between the barrel and the action. By using bushings of different inside diameters, Bill can fit any barrel up to an inch or so diameter, so long as it has a straight contour at the breech end. To mount the barrel, Bill simply places the fitted bushing over the barrel end-shank, then slips the “sleeved” barrel into the front end of the action. Tighten three bolts, and the barrel is secure.
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March 21st, 2021
This article was originally written by noted rimfire gunsmith Bill Myers. Sadly, Bill passed away in May 2010, but his legacy lives on. He pioneered many advancements in rimfire gunsmithing and Myers-built guns still win matches in benchrest competition.
Crafting competitive rimfire benchrest rifles is considered an art as much as a science. The smith must understand subtle, yet critical aspects of vibration control, barrel tuning, and rifle balance. In the United States, only a handful of gunsmiths consistently turn out rimfire BR rifles that consistently run at the front of the pack at major matches. Bill Myers was one of those master craftsmen. In this article Bill discussed the process of building a winning rimfire BR rig. He reveals some interesting secrets, including his procedures for testing bedding performance and his barrel indexing system. Bill’s methods obviously work, as the Suhl-actioned rifle featured here won a truckload of trophies in its very first match.
Building a Match-Winning Rimfire Benchrest Rig
by Bill Myers
In my opinion, a winning rimfire benchrest rifle is probably twice as difficult to build as a competitive centerfire rifle. The relatively slow .22 LR bullets stay in the barrel much longer than centerfire bullets. This means that vibration control is critical. Likewise bedding is critical. Bore finish and lapping are very important. The amount of bore taper or “choke” can have a huge effect on accuracy. Ignition is also very important and above all, rimfire BR rifles need a very stable stock that tracks perfectly. A rimfire that shoots great is a complete marriage of all components and of the shooter’s need to be aware of everything possible.
Click Photo to Zoom
The rifle featured in this article was built from scratch with attention to all the details that go into accuracy. The goal was to build a gun that could win from the get-go. This would be a “Spec Gun”, meaning a rifle that was personally tested and tuned by me for optimum performance before it went out to the customer.
The Suhl trigger is as good as it gets so no change was needed. It easily adjusts down to about 2 ounces.
Baer Stock in Bubinga Wood
There are many choices when you start to build a complete rifle. It has to shoot well and it has to catch ones eye, or it’s just another rifle on the line. I prefer wood stocks on rimfires for two reasons: they are very stable if the right wood is used and they have a certain traditional appeal to many shooters. I chose Bubinga wood for this particular gun because it is very stable and heavy, it has a very dense grain and a very pronounced figure with a natural red color. The Bubinga is a very forgiving wood to work with.
Gerry and Bruce Baer in Pennsylvania do all my stock blanks. I do all my own inletting and bedding. The blank weighed 4.5 pounds when it came off of Bruce Baer’s duplicator. This Bubinga wood is so hard that it did not need pillars, but I put them in anyway. I bed all my stocks with Loctite Steel Bed liquid and add filler to desired thickness. The final bedding is done with an aircraft tooling epoxy that does not deteriorate over time. The stock has an ebony butt plate and six (6) coats of automotive clear, polished to a “high buff” finish.
Suhl 150-1 Action
 Accurized and BN-Nickel Plated
I used a new, unfired Suhl 150-1 action. As explained in the sidebar below, the Suhl 150 actions were originally crafted in East Germany for position rifles. They have a very fast lock-time and come with an outstanding trigger. However, they need some work when adapted to a modern BR gun. The action needed to be accurized and threaded. I have a special tool that I use to accurize actions. It uses two sets of spiders for dialing-in the bolt raceway. After the bolt raceway is running true, one can thread and true up all bearing surfaces so that everything is in perfect alignment with the action raceway bore.
 BN-Nitride Plating on Action
I decided to plate the action and all bolt parts with Boron Nitride nickel plating. I bough the BN Electroless Nickel Kit from Caswell Plating and did the job myself. I started by bead-blasting the action so that it would end up with a “satin” finish. The plating material is then applied in a tank. The Boron Nitride goes directly into the plating solution, but you need to use a pump to keep the solution agitated so the BN distributes evenly.
Once the action is completely ready (the metal must be perfectly prepped, with no contaminants), the process goes easily and can be completed in about half an hour. The end result is a very slick, low-friction finish, that is .0002″ (two ten-thousandths) thick and hard as glass. The Boron Nitride makes everything very smooth. After the plating job, the action was noticeably slicker than before.
The cone breech (photo below) permits the barrel to be INDEXED (rotated around bore axis) to any position on the clockface. You then test various rotation settings to find the best accuracy. The system does work. Some barrels shoot best in a particular rotational setting. E.g. with index mark at 3 O’clock vs. 12 O’clock.
 Fitting and Chambering the Barrel
As for a barrel, I had two good choices: one Shilen 1:16″-twist, 4-groove ratchet and one Benchmark 1:16″-twist, 3-groove. Both barrels were very accurate and at the end, I decided to leave the Shilen on the rifle because I wanted to put the Benchmark on another Suhl I’ve set aside for myself. I chambered the barrel for Eley flat nose EPS. We’ve found the gun also shoots the new Lapua X-ACT ammo very well.
The barrel finished at 25″ long and features a tuner by the Harrell brothers of Salem, Virginia. I use a flat 90° crown–it’s the most accurate and its gives a good seal against the tuner. I also use a 45°, 12-flute cutter that leaves no burr when cutting the crown. This chamfer protects the crown when cleaning the barrel. There is no sharp edge for the brush or jag to hit on the return stroke. The barrel was headspaced at .043″ and I use a tapered reamer ground by Dave Kiff of Pacific Tool & Gauge in Oregon. The chamber leade area is lightly polished to remove reamer burrs. The breech end of the barrel is machined with a 1/2″ ball end mill to produce what I call a “Myers cone breech.” Technically, it has a sloping radius as you can see, rather than a straight-sided cone. Finishing the breech in this fashion facilitates indexing the barrel, as the barrel can be rotated to any position (on the clockface), without requiring new extractor cuts.
| Barrel Indexing — Finding the “Sweet Spot”
When indexing a barrel, one rotates it to different clockface positions relative to the action. Imagine marking a barrel at TDC or 12 o’clock, and then rotating it so the mark is at 3 O’clock, 6 )’clock, 9 O’clock and so on. At each position one shoots groups to determine at which index setting best accuracy is achieved.*
I know that barrel indexing is controversial. I don’t want to get into a lengthy debate other than to say that I believe that careful and thorough testing can reveal a “preferred” index position for a good barrel. With the barrel set in that particular position relative to the action I believe the barrel can yield optimal performance.
I perform the indexing tests indoors at 50 yards. I use a rail-gun with floating action. The barrel is held in place with a clamping fixture similar to an Anschutz 2000-series action. Basically, two vertically-stacked metal blocks clamp around the barrel. I can index the barrel this way simply by unclamping the barrel blocks, rotating the barrel and then re-clamping the system. I have a special system so the action can stay in the same position, even as the barrel is rotated.
It takes time and effort to get solid indexing results. Normally I shoot at least 400 rounds of ammo in 3-4 indexing sessions. Shooting a handful of groups is not enough. You may think you’ve identified the best index position, but you need to shoot many more rounds to verify that. Also, in a very good barrel, the effects of indexing may be subtle, so it will take many groups to confirm the optimal position. In my experience, really good “hummer” barrels do not benefit as much from indexing as an “average” barrel.
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 Accuracy Testing with Both Barrels
I tested the rifle indoors at 50 yards at the Piney Hill Benchrest Club range. There was no finish on the stock, but it shot well in my one-piece rest with the Benchmark 16-twist, 3-groove barrel and no added weight on the tuner. I shot 30 rounds of Eley Match EPS Black Box (1064 fps) and had 25 Xs and five 10s on the IR 50/50 style target. Not too shabby for a new barrel with no special break-in.
When the Shilen barrel arrived, I installed it on the rifle. By this time the stock had been clear-coated and finished, and the action had been polished and plated. I shot the Shilen barrel outside since it was too hot in the building. The first target was a 250-19X with a new lot of Eley Match EPS Black Box (1054 fps). The gun shot well. My friend Tony Blosser asked to shoot the gun, and he drilled a 250-20X in a steady wind using the same Eley ammo. See target at right.
| Advanced Procedures — Vibration Control and Tuner Position
Barrel Tuning Using 2-Way Electronic Indicators
Before competing with this rifle, I put it in a firing fixture I use to tune the barrel. I employ a pair of very expensive Swiss 2-way electronic min/max hold indicators. These measure both up movement and down movement of the barrel as the gun is fired. I can measure the actual vertical travel of the barrel at any position from the front of the receiver to the tuner. I can also tell how long the barrel vibrates, time-wise. Using this fixture I found that the Shilen barrel was very consistent in readings and seemed to work well with no additional weight on the tuner. No barrel ever stops vibrating completely — but this was close, showing less than .002″ of total movement.
Bedding and Vibration Control
I have found that measuring the actual movement of the barrel during firing tells me a lot about the quality of the bedding. I have learned that if I see very big movements (e.g. .010″ up and .005″ down), then there may be a problem with the bedding. I saw this kind of big swing on a rifle with bedding that had not cured properly.
Another pattern I watch for is uneven vertical movement. For example, if the barrel vibrates .008″ up but only .002″ down, that tells me the bedding has issues. As noted above, I look for minimal vibration travel (after the tuner is fitted and optimized), and I also want that travel to be relatively equal both up and down. Good rimfire gunsmiths agree that proper bedding has an important influence on vibration control and tuning. By measuring actual barrel movement during firing, we can, to an extent, quantify how well the bedding is working. At a minimum, we can see if there’s a serious bedding problem. |
Trial by Fire — Shooting the Gun in Competition
After semi-gluing in the action, the rifle was shooting great. So, I decided to take it to the Maryland State Unlimited Championship to see if it was truly competitive — whether it could “run with the big dogs”. As it turns out, the Bubinga Suhl was more than just competitive. The rifle won three of the six cards and won the meters championship. In the photo below you can see all the trophies the gun won in its very first match. One of the other competitors in Maryland, dazzled (and perhaps a bit daunted) by the Bubinga Suhl’s stellar performance, told me: “Sell that gun Bill. Whatever you do, just get that darn rifle out of here.” Confident that this was a rifle capable of winning major matches, I packed up the rifle and shipped it to Dan Killough in Texas. Killough has shot some impressive scores with the gun.
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Suhl Target Rifles — East Germany’s Legacy
Suhl 150 rifles were manufactured in former East Germany (GDR) by the Haenel firearms factory in the town of Suhl. This region has a long history in arms production. In 1751, Sauer & Sohn founded the first German arms factory in Suhl. Following WWII, Suhl 150s were produced for Communist Bloc marksmen, including East German Olympic shooters. Prior to German unification, the East German national shooting arena was located at Suhl and hosted many top-level competitions including the 1986 ISSF World Championships.
Superb Rifles with Amazing Triggers
As a product of East Germany, the “mission” of the Suhl 150 was to rival the accuracy of the Anschütz, Walther and other premium match rifles built in the West. East German shooting teams wanted to finish on top of the podium, so they needed a rifle with superb inherent accuracy. The Suhl 150s have an outstanding trigger that can be adjusted down to about two ounces. The Suhl 150 action, like the Anschütz 54, boasts an extremely fast lock-time — an important factor in a position rifle. And Suhl barrels were legendary for accuracy.
Suhl 150 Benchrest Conversions
Many of the first used Suhl 150s that made it to America were converted to Benchrest rifles because the action/trigger/barrel combination was unbeatable for the price. Some of the barrels on these “surplus” Suhls were phenomenal — as good as any custom barrels available today. It was not unknown for a Suhl 150 barreled action, transplanted into a benchrest-style stock, to win BR matches with the original barrel. Today, however, most of the Suhl benchrest conversions end up with modern, American-made barrels. While some older Suhl barrels can “shoot with the best of ‘em”, new barrel designs optimized for use with tuners have an edge, at least in benchrest circles. That’s why builders such as Bill Myers swapped out the Suhl barrel with something like a Benchmark reverse-taper two-groove.
 Today Suhl 150 rifles are very hard to find in North America. In 2006, a used Suhl 150, even without sights, might fetch $1200.00 or more. Then, in 2007 through early 2008, hundreds of Suhl match rifles were imported. This drove prices down, and those “in the know” snapped up complete Suhl 150s at prices ranging from $450 to $850 (see 2007 advert at right), depending on condition.
Many of these rifles were left “as built” and used successfully in prone competition. Others were converted into benchrest and silhouette rifles, “parted out” for the actions and triggers. If you were able to grab one of those imports at a good price–consider yourself lucky.
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* Bill Myers actually created his own clamping rimfire action to facilitate barrel indexing. CLICK HERE for Myers Rimfire Action. To index the barrel, Myers simply loosened three clamping-bolts and rotated the barrel in the action. Because there is no thread to pull the barrel in or out, the headspace stays the same no matter how much the barrel is rotated. With a threaded action, you might have to use shims to test different rotational positions, or otherwise re-set the shoulder with each change.
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October 17th, 2009
LINK: Bill Myers’ Indexable Rimfire Action
Does the rotational position of a rimfire barrel (relative to the action) affect accuracy? Many smart folks think it does. But how can you set the barrel at different rotational orientations to find what position works best. Bill Myers came up with a clever answer. Using a cone breech (so extractor position doesn’t matter), Bill fits a bushing on the end of the barrel, which is then clamped by the action.. This allows the barrel to be rotated without altering headspace.
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October 20th, 2008
Gene Beggs is a Texas shooter and gunsmith known for “out of the box” thinking. He has successfully pioneered the 220 Beggs and 6mm Beggs cartridges in BR competition, and has developed radical new rifle designs and tuners at his West Texas research facility (with a 100-yard indoor shooting tunnel). Recently Beggs has tackled the challenge of indexing centerfire barrels. It looks like he has engineered a workable solution that will allow shooters to index their barrels without altering the critical headspace dimension. If this really works, Gene has come up with an important new gunsmithing procedure with the potential to enhance accuracy for a wide variety of firearms.
Barrel Indexing Basics
Barrel Indexing is a procedure for optimizing the rotational position of a barrel relative to the action. With a conventional barrel installation, if you were to put a mark on the outside of a barrel and then screw the barrel into the action, that mark might end up at at 12 o’clock, or 6 o’clock or pretty much any position on the “clock-face”, depending on where the shoulder is cut on the barrel. When the shoulder butts up against the face of the action (or recoil lug), you can’t screw the barrel in any farther. At that point, the barrel’s rotational position is fixed and can’t be changed without altering headspace.
Tests with rimfire barrels suggest that careful barrel indexing can produce accuracy gains. We’re not quite sure why — there are different theories — but it has been clearly demonstrated that by rotating the barrel relative to TDC (top dead center) on the action, you can move bullet point of impact quite dramatically. On rimfire barrels machined with a cone breech and secured with a barrel block system (as on an Anschutz 2000-series action), gunsmiths such as Mike Ross have been able to easily experiment with index positions. CLICK HERE for Mike Ross Indexing Tests.
But indexing centerfire barrels has been a challenge. You can use shims to adjust the barrel’s index position relative to action TDC, but this moves the shoulder in and out, effectively altering headspace by the width of the shims used.
Is there a way to index a centerfire barrel without changing the headspace? Texas Benchrest shooter and gunsmith Gene Beggs thinks he has the answer.
The Beggs Barrel Indexing Solution
With a conventional barrel installation, the action/receiver has an internal female thread. The threaded breech end of the barrel, or tenon, has a male thread. The barrel simply screws in until its rotation is stopped (and index position fixed) when the shoulder hits the action face or recoil lug.
Beggs has come up with an ingenious solution using an intermediary threaded bushing that fits between the action thread and the tenon threads. The barrel tenon is reduced in diameter slightly and re-threaded to mate with the inner bushing. This inner bushing is shorter than the receiver threads so it can be adjusted inwards and outwards. Its position is fixed with a set-screw. The effect of moving the inner sleeve inwards and outwards is to change the index position at which the barrel tenon threads start to “grab” as they are spun inwards. Set the inner sleeve at one position, and the tenon threads may start contact at 6 o’clock for example. Rotate the inner sleeve a half-turn and the threads will start at 12 o’clock.
Now, as you continue to screw the barrel inwards, it will still stop when the shoulder hits metal — so headspace is always the same. But…and this is the key point, the barrel’s rotational index position will vary depending on the position of the inner bushing. By adjusting the bushing position, you control where the barrel’s threads start to “connect”. The result is that the rotational orientation of the barrel can be indexed at any point on the dial.
Boyd Allen has given this example which may help readers visualize things: “Think of a slot-head machine screw being tightened till it bottoms. The final orientation of the slot after tightening depends on where it picks up the first thread of the threaded hole. If the hole itself is rotated then the final position of the slot, relative to the viewer, will be rotated by a similar amount. Screw a slot-head machine screw all the way into a nut. Now turn the nut. The slot rotates with it.”
System Slated for Production
Gene Beggs is excited about the new indexing system and plans to create a kit that can be used by gunsmiths. Gene writes:
“Inserted in between the action threads and the barrel tenon is a bushing that can be adjusted fore and aft in the action. This makes it possible for the barrel tenon shoulder to contact the receiver face at any position of the clock. Of course, the barrel tenon must be turned down and threaded to match the inside threads of the bushing. A small stainless steel set screw now holds the bushing securely in place. Adjustments are quick, easy and secure.
I spent two days in the tunnel testing the system. The test rifle is a Cobra sporter chambered in 6mm Beggs stocked with one of my Ultralite aluminum stocks. Barrel torque was rechecked each time the barrel was re-indexed and never seemed to loosen up. The sweet spot was found on the second adjustment at the six o’clock position. After a couple of days of testing, I now have complete confidence in the rifle and indexing system. Unless problems arise, we will soon be tooling up and producing kits which will require gunsmith installation.”
For more information on the Beggs Indexing system, email Gene at genebeggs [at] cableone.net, or call (432) 631-5124, or (432) 367-0329.
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