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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January 8th, 2013

Centerfire Benchrest Shooters Explore Benefits of Tuners

Barrel tuners have been used successfully in rimfire benchrest for many years (see photo below). 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.

Anschutz Tuner

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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