Tonight I ran one of my PCP guns over the chronograph and thought I'd share the results.
Tests and results
I shot 8 shots starting at each of the PSI levels listed below. After those 8 shots, I recorded the crony data and began a new 8 shot group from the PSI that remained in the tank. This is a .22 pistol shooting 21 grain pellets.
2900 PSI - 522 fps avg with Std Dev of 11.8
2750 PSI - 550 fps avg with Std Dev of 8.6
2500 PSI - 566 fps avg with Std Dev of 4.2
2050 PSI - 561 fps avg with Std Dev of 6.9
1750 PSI - 530 fps avg with Std Dev of 14.8
This clearly shows that for this particular gun, with this pellet, a starting PSI of 2500 produces both the highest velocity and the lowest shot-to-shot variation.
I'd always heard people talk about their "optimal fill pressures" but it was cool to validate it on one of my own guns.
I'm going to shoot targets tomorrow to see if these variations have a material impact on grouping.
Tests and results
I shot 8 shots starting at each of the PSI levels listed below. After those 8 shots, I recorded the crony data and began a new 8 shot group from the PSI that remained in the tank. This is a .22 pistol shooting 21 grain pellets.
2900 PSI - 522 fps avg with Std Dev of 11.8
2750 PSI - 550 fps avg with Std Dev of 8.6
2500 PSI - 566 fps avg with Std Dev of 4.2
2050 PSI - 561 fps avg with Std Dev of 6.9
1750 PSI - 530 fps avg with Std Dev of 14.8
This clearly shows that for this particular gun, with this pellet, a starting PSI of 2500 produces both the highest velocity and the lowest shot-to-shot variation.
I'd always heard people talk about their "optimal fill pressures" but it was cool to validate it on one of my own guns.
I'm going to shoot targets tomorrow to see if these variations have a material impact on grouping.
