I have noticed That a higher reg pressure (+/- 135 bar) to achieve a similar velocity has yielded lower extreme spreads, within reason. It also seems that I get a better shot count, even though I can get the same velocity with a reg pressure of 90 bar. It seems that using less hammer tension results in the valve closing sooner and therefore more efficiently. At 90-100 bar, with more hammer it seems there is still air being released after the pellet has left the barrel. This timing is also important to accuracy since continuing to expel turbulent air at the skirt of the pellet exiting the barrel can lead to stabilization issues. Many videos talk about finding the "harmony" or "sweet spot" with an Impact. here's what I do:
Set reg to 135 shoot pellet of choice at various hammer tensions until I get to the velocity that yields best accuracy (9000 for sake of argument). Then add 5 bar of reg and adjust hammer back to the best speed. Repeat this process both above and below the 135 setting until the accuracy is best. It almost always seems to be the most accurate at the same place it is the most efficient. There is a point where the air is not being released after the pellet has left. It will be quieter and smoother at the same velocity. You can actually hear and feel the difference, most importantly, it shows up on the target!
Remember free advice is only worth what you paid for it.
Your mileage may vary, (significantly).
