Fascinating Test Shows Tuner Settings Can Alter Point of Impact
Have 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
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)
Right Half of Target Strip (shots with 1/4 rotation change of tuner in sequence)
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.
The rifle features Carlito’s CG thunderbolt action, in a low-profile carbon-fiber stock also made by Gonzales. Up front is a Bukys-style tuner. If you watch the video carefully, you may wonder “how do the cartridges get into the action?”, since you won’t see the shooter (Carlito) pulling rounds from a loading block. Well the secret is that metal contraption to the left of the gun. It is a gravity-fed caddy connected, via cable, to a hand control. After working the bolt to extract a fired case, the shooter can push a button and the next round drops down from the upper left into the left port/right eject action. Simply close the bolt and you’re ready to roll. For more information, visit 
