I've owned an Air Arms S500 in .22 caliber for a while. I know it loves the 18.13g JSB's the best. Sadly, due to newer guns, this one didn't get as much attention.
Fast forward to Thanksgiving weekend and Black Friday and there was a great deal on the bluetooth module for the ProChrono digital. One of the best purchases for anyone really interested in reviewing their data to help with tuning.
Today I had a chance to see just what the power adjuster really does to the gun's performance.
For the longest time, I knew that the Air Arms power wheel adjusts the transfer port size, thereby restricting air flow and allowing for the user to adjust power output of the gun. It did not do anything to change the overall shot count of the gun.
It's also known that Air Arms S510/500's have no hammer spring adjustment, internal or external. Most people interested in adjusting this feature were forced to modify the original hammer weight, hammer spring, especially when installing an aftermarket regulator.
What the power wheel actually does is more than just control velocity. It also directly affects the power curve, extreme spread, and standard deviation. This result is similar to what a hammer spring adjustment would achieve, but unfortunately, because the power wheel does multiple things, it is a "jack of all trades, master of none" kind of feature. Because there is no regulator in the gun, you cannot improve efficiency at a desired power output. Instead, you restrict power output, and the extreme spread and standard deviation changes for the better or worse, depending on which way you adjust the power.
The other major factor to consider is accuracy. Certain pellets like to travel certain speeds in order to achieve the best accuracy. So while I could achieve better ES and SD's, accuracy suffered a little at lower velocities.
Through my testing, the gun is most accurate with the 18g JSB's at speeds between 830 and 860 fps.
Here are serial back to back 5 shot groups at 55 yards with velocities in this velocity range.
So here's the data based on four different power settings:
The starting pressure for all tests was 190 bar, with the ending pressure just above 100 bar after 40 shots.
Ammo was the JSB 18.13g for all tests.
I settled on the 65% power setting, which gives me better accuracy despite a slightly higher ES and SD compared to the 60% power setting.
Overall, I'm quite impressed at what this gun can do and how the power wheel affects the overall power curve of the shot string.
Conclusions:
1. At 50 yards or less, this gun will put down 1/2" groups with ease.
2. Shot count is roughly 40 per fill to keep the POI from shifting more than 1 inch towards the end of the shot string/lower fill pressure.
3. I can get roughly 28 shots per fill and keep ES to 30 fps using the 65% tune.
4. If you want maximal power, of course, set the power wheel to 100%, shoot 15 shots, then refill back up to 190 bar.
5. If you want a flatter shot string, drop the power by at least 25-40% to suit your specific needs.
6. Very versatile using older tech to achieve variable power output, especially without a regulator.
7. Do the "O-ring" fix for the power wheel. Place an o-ring behind the wheel to keep it from rotating freely, thus locking in your adjustments without fear of accidentally bumping it out of tune.
Hope this helps anyone out there with an S510/500 or anyone considering these guns for their collection. They truly are works of art and very reliable with little to no maintenance.
Fast forward to Thanksgiving weekend and Black Friday and there was a great deal on the bluetooth module for the ProChrono digital. One of the best purchases for anyone really interested in reviewing their data to help with tuning.
Today I had a chance to see just what the power adjuster really does to the gun's performance.
For the longest time, I knew that the Air Arms power wheel adjusts the transfer port size, thereby restricting air flow and allowing for the user to adjust power output of the gun. It did not do anything to change the overall shot count of the gun.
It's also known that Air Arms S510/500's have no hammer spring adjustment, internal or external. Most people interested in adjusting this feature were forced to modify the original hammer weight, hammer spring, especially when installing an aftermarket regulator.
What the power wheel actually does is more than just control velocity. It also directly affects the power curve, extreme spread, and standard deviation. This result is similar to what a hammer spring adjustment would achieve, but unfortunately, because the power wheel does multiple things, it is a "jack of all trades, master of none" kind of feature. Because there is no regulator in the gun, you cannot improve efficiency at a desired power output. Instead, you restrict power output, and the extreme spread and standard deviation changes for the better or worse, depending on which way you adjust the power.
The other major factor to consider is accuracy. Certain pellets like to travel certain speeds in order to achieve the best accuracy. So while I could achieve better ES and SD's, accuracy suffered a little at lower velocities.
Through my testing, the gun is most accurate with the 18g JSB's at speeds between 830 and 860 fps.
Here are serial back to back 5 shot groups at 55 yards with velocities in this velocity range.
So here's the data based on four different power settings:
The starting pressure for all tests was 190 bar, with the ending pressure just above 100 bar after 40 shots.
Ammo was the JSB 18.13g for all tests.
I settled on the 65% power setting, which gives me better accuracy despite a slightly higher ES and SD compared to the 60% power setting.
Overall, I'm quite impressed at what this gun can do and how the power wheel affects the overall power curve of the shot string.
Conclusions:
1. At 50 yards or less, this gun will put down 1/2" groups with ease.
2. Shot count is roughly 40 per fill to keep the POI from shifting more than 1 inch towards the end of the shot string/lower fill pressure.
3. I can get roughly 28 shots per fill and keep ES to 30 fps using the 65% tune.
4. If you want maximal power, of course, set the power wheel to 100%, shoot 15 shots, then refill back up to 190 bar.
5. If you want a flatter shot string, drop the power by at least 25-40% to suit your specific needs.
6. Very versatile using older tech to achieve variable power output, especially without a regulator.
7. Do the "O-ring" fix for the power wheel. Place an o-ring behind the wheel to keep it from rotating freely, thus locking in your adjustments without fear of accidentally bumping it out of tune.
Hope this helps anyone out there with an S510/500 or anyone considering these guns for their collection. They truly are works of art and very reliable with little to no maintenance.
