December 12th, 2018

Tuning Barrels for Enhanced Precision and Accuracy

Anschutz Tuner

When a shot is fired through it, a barrel will exhibit harmonics. Tuning these harmonics (the “waves” that propagate through the barrel) can alter point of impact and, if you’re lucky, reduce group size. Barrel tuners have been used successfully in rimfire benchrest for many years (see photo above). While there are competing theories as to how and why barrel tuners work on rimfire rifles, there is no question that the accuracy of some rimfire barrels can be improved with the addition of a tuner. By changing the position of weights at the end of the barrel, we’ve seen shooters shrink their average group size as well as adjust the “sweet spot” for different lots of rimfire ammo. On the other hand, tuners can be the source of great frustration; some installations may yield little or no benefit. A shooter may have to experiment with a variety of different tuner designs (and weights) to find the optimal configuration.

Gene Bukys Barrel Tuner 333smittyCenterfire Tuners–Still a Work in Progress
In centerfire benchrest competition, the vast majority of competitors do not use tuners, though a few short-range shooters such as Gene Bukys and Jackie Schmidt have enjoyed considerable success. Gene has won major championships with tuned rifles. In 2011 Gene won both the Super Shoot and World Benchrest Championship (WBC), and Gene recently set a new NBRSA Sporter Class Grand Agg Record.

Centerfire benchrest guns typically employ shorter barrels with a much fatter contour (larger diameter) than rimfire rifles. Because centerfire rounds produce much higher pressures and velocities that a 22LR, a centerfire barrel also exhibits much different vibration characteristics than a typical rimfire barrel. Nonetheless, there are pioneers working with centerfire tuners who believe that tuning may be the “next leap forward” in centerfire accuracy.

Shown below is a switch-barrel benchrest rifle built by Forum member Eddie W. of Texas. It features a dual-port Hall “M” action with a ShadeTree Engineering Tuner crafted by Butch Lambert. The gun is designed to take both a 6PPC barrel for group shooting and a 30BR barrel for score shooting. The gun was barreled by Wayne Shaw, and Eddie did the stock work himself. Eddie reports: “It is a very accurate rifle.”

Lambert Tuner

Will we see more tuners on centerfire rifles? Only time will tell. Some folks believe that, since one can easily adjust the loads shot by centerfire guns (by tinkering with the powder charge and seating depth), tuners have limited utility. On the other hand, tuner advocates such as Gene Beggs believe tuners can help keep your group sizes small even as conditions (temperature, humidity) change. Gene believes that, with an appropriate tuner, you can spend less time fiddling with the load specs (changing your powder charge) and instead “dial in” your sweet spot using the tuner.

Lambert Tuner

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October 4th, 2014

Fascinating Test Shows Tuner Settings Can Alter Point of Impact

6PPC Pascal Fischbach Bukys Barrel Tuner sine waveHave a good look at the photos below — this may be one of the most noteworthy target strings we’ve ever published. What you can see is the effect of barrel tuner position on point of impact (POI). You can clearly see that the tuner position alters the up/down POI location in a predictable fashion.

This remarkable 15-shot sequence was shot by French benchrester Pascal Fischbach using his 6 PPC fitted with a CG (Carlito Gonzales) action and a Bukys barrel tuner.

Pascal reports: “After [bullet] seating and load validation, I put the Bukys tuner on, screwing it out 10 turns. According to Carlito, the CG’s super stiff action-to-barrel fit gives a faster vibration modulus that is detrimental below 10 turns [position of the tuner].” Pascal’s procedure was to screw out the tuner 1/4 turn progressively from one shot to the next. He shot one bullet at each tuner position, with a total of 15 shots.

15-Shot Sequence with Tuner Changes
6PPC Pascal Fischbach Bukys Barrel Tuner sine wave
CLICK HERE to SEE Large Version of Complete Test Strip (All 15 shots in a row).

Left Half of Target Strip (shots with 1/4 rotation change of tuner in sequence)
6PPC Pascal Fischbach Bukys Barrel Tuner sine wave

Right Half of Target Strip (shots with 1/4 rotation change of tuner in sequence)
6PPC Pascal Fischbach Bukys Barrel Tuner sine wave

Pascal observed: “Note the point of impact displacement [from shot to shot] tracks clearly along a sinusoide (sine wave curve).” This is indeed notable and significant! This shows how the tuner’s ability to change barrel harmonics can alter the position of the muzzle as each bullet exits, resulting in a higher or lower POI. Pascal sent his results to Carlito Gonzales in Argentina for analysis.

Pascal poses this question to readers: “Guess which three positions Carlito recommends to try?”

Editor’s Note: While this target sequence clearly shows how tuner position can alter bullet point of impact, this, by itself, does not tell us which tuner position(s) are best for accuracy. That will require further multi-shot group testing, involving careful experimentation with tuner position (and powder charge weights). But for those folks who doubt that a tuner can make a difference on a short, fat barrel, just take another look at the photos. The up/down changes are undeniable, and noteworthy in the wave pattern they follow.

6PPC Pascal Fischbach Bukys Barrel Tuner sine wave

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July 7th, 2010

Details of Jackie Schmidt’s .1118 100-Yard “Agg for the Ages”

As word spreads of Jackie Schmidt’s historic 0.1118″ 5-target 100-yard Heavy Varmint Aggregate, many readers have inquired about Jackie’s gear and loading procedures. Interestingly, Jackie tells us that he selected the 30 BR “on a whim” for the Heavy Varmint stage of the Midland tournament, after he couldn’t get his 6 PPC Light Varmint gun to shoot up to his standards. With the PPC, he was getting some erratic vertical, with one shot popping up to spoil the group. Jackie turned to his trusty 30 BR, and, as they say, “the rest was history”. Jackie says his 30 BR “held perfect tune all day long”, with “absolutely no vertical”. Here are some other interesting facts about Jackie’s amazing 0.1118″ 5x5x100 Agg and the 30 BR he steered to the pending NBRSA record.

Jackie Free Recoils his 30 BR
Unlike many 30 BR shooters who shoulder their guns, Jackie shoots his 30 BR totally free recoil: “The only thing I touch is the trigger. I try to keep my body out of the equation. Free recoiling a 30 BR isn’t that difficult with a true 13.5-lb rifle.”

30 BR cartridge
30 BR file photo. Jackie Schmidt does not shoot Moly bullets normally.

Jackie Didn’t Clean During Record Agg
Jackie shot his entire 100-yard HV Aggregate (25 rounds plus sighters) without cleaning his 30 BR rifle. Jackie told us: “I never cleaned the rifle until the end of the day. In fact I never took the gun out of the bags.” Jackie tells us that shooting a full Agg without cleaning has become standard practice with 30 BRs: “We’ve all learned that you don’t have to clean them. It’s a phenomenon of the 30 calibers. They shoot just as good on the last shot as the first shot.” When he does clean, Jackie uses patches soaked with Butch’s Bore Shine, followed by 10 strokes with a wet brush, then dry patches. Jackie adds: “For the past few years, I’ve never put any solvent but Butch’s in my bores.”

Hodgdon H4198 powderJackie Used 100% Case Capacity Charge
Jackie loaded a “100% usable case capacity charge” of Hodgdon H4198 (Extreme) in his rounds. His 112gr BIB bullets are “just kissing” the top of the powder column. To achieve that fill level, Jackie uses an 8″ drop tube. “That’s an old PPC-loader’s trick,” Jackie tells us. He added that his lot of H4198 is slower than most. He’s found that “some guys can reach the 3000 fps mark using nearly a full grain less powder than me.” But we wonder if loading at 100% of case capacity helps with accuracy? Folks with a faster lot of H4198 might not be able to reach 100% case capacity.

Jackie Schmidt’s ‘Snubber’ Tuner — The Inside Engineering
Everyone wants to know about Jackie’s “snubber” tuner, shown in the photo below. The Tuner is made from aluminum and brass and weighs 5.5 ounces. The tuner is 2 5/8″ long and extends past the true crown 5/8″. The inner cylinder is aluminum while the outer section is a marine bearing consisting of a brass shell with hard rubber vulcanized to the inside diameter. (These brass/rubber marine bearings are used for propeller shaft seals). The sandwiched brass/rubber bearing is then pressed on to the central aluminum shaft. The hard rubber helps dampen vibration. The tuner screws on and then is “locked” in place with a split clamp (the last 2″ of the barrel is threaded).

30 BR cartridge

Unlike most tuners which have a fixed base and forward, rotating ring, Jackie’s tuner is one integrated unit. To adjust tune, Jackie’s “snubber” tuner is unclamped at the base and the whole assembly is screwed in or out on the threaded barrel. Jackie machined a very tight-pitched barrel thread so a full rotation of the tuner produces only .028″ of fore and aft movement. Jackie tells us that, once the basic position is set for a barrel, it doesn’t take much rotation to set the tune. He can usually optimize the barrel tune with less than 1/2 turn of the tuner. After the tune position is set, the split clamp at the inboard end is tightened. This way the tuner is basically locked in place while shooting.

Despite numerous requests, Jackie does not sell his tuners commercially. But someone with good machine skills could build a clone tuner. Team USA benchrest shooter Gene Bukys crafted a similar snubber-type tuner which he used successfully at the 2009 World Championships in South Africa.

The “25 Shots Heard Round the World”
Even people outside the Benchrest community are excited about Jackie’s 0.1118 Aggregate. Jackie’s achievement was noted by Michael Bane and broadcast on the Downrange TV Weekly Video Podcast.

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