Take a look at the photos. This may be one of our most notable target strings. You can see the effect of barrel tuning position on point-of-impact (POI). You can see that the barrel tuner position changes the up/down location of the POI in a predictable manner. This 15-shot sequence, shot by French benchrester Pascal Fischbach with his 6 PPC fitted a CG action (Carlito Gonzales), and a Bukys bar tuner. Pascal Fischbach reports: “After [bullet] loading and seating, I screwed out the Bukys barrel tuner 10 turns. Carlito claims that the super stiff action-to barrel fit of the CG gives a faster vibratory modulus, which is detrimental below 10 rotations [position of tuner]. Pascal’s procedure involved screwing out the tuner 1/4 turns progressively as he went from one shot to another. He fired one bullet per tuner position for a total 15 shots. 15-Shot Sequence With Tuner Changes
Click Here to See Large Version of Test Strip Complete (All 15 Shots in a Row). Left Half of Target Strip
Right Half of Target Strip
Pascal noted: “Notice the point of impact displacement (from shot to shot) tracks clearly along a sine wave curve.” This is certainly notable and significant! This shows that the tuner can change barrel harmonics to alter the position of each muzzle as the bullets exit, resulting in higher or lower POI. Pascal sent his results to Carlito Gonzalez in Argentina for analysis. Pascal asks readers to guess which three positions Carlito Gonzales recommends. Editor’s note: While this target series clearly shows how tuner positioning can alter bullet impact point, it does not tell us what tuner positions are best for accuracy. This will require more multi-shot testing, which involves careful experimentation with the tuner position. If you doubt that a tuneer can make any difference on a barrel with a short and fat length, take a look at these photos. The up/down adjustments are obvious, and the wave pattern that they follow is noteworthy. Shooting Setup and Test Conditions
Pascal performed this test in very good weather conditions at his home range. “This was shot outdoors with four Smiley Flags. The range is located in a narrow cut of high woods. The wind was consistent and the flags were readable. I started by testing the tuner at 10 turns and then went to 15. I recently… found the sweet spot close to the rearmost position. The rigidity provided by the super long tenon was not a good reason to ignore the recommended Bukys tuner tuning procedure.”
