Theory - Power plenum is a negative for low powered shooting.
What is your experiences?
Some time ago I installed a power plenum on my pcp for the obvious purpose of shooting heavy pellets and slugs at higher speeds. After using it for a while I moved away from heavy pellets and especially slugs and use mostly 18gr pellets.
I then wanted to shoot light 14gr pellets at lower speeds but did not lower the regulator pressure. - Yes I know I should but it was set perfectly for 18gr which is my main pellets and I did not want to change it. - (EDIT - I should have said - I did adjust the hammer spring to a lower setting to get the best from the 14gr pellets.) What I experienced is that it would have a big extreme spread in speed. My theory is that once the regulator let air through to the power plenum, the air consumption per shot is to low for the plenum pressure to drop enough for the regulator to open after each shot. It takes a 5 shot cycle for the regulator to open again. Because of this the pressure and thus speed goes up and down and give vertical stringing. Once the regulator open, the speed is lower because of lower hammer, ,remember the regulator is set for 18gr at higher speed, and speed increases as the plenum pressure drop. Once the regulator open again the speed drop again. Speed confirmed by chronograph.
That is why one should have a smaller plenum and adjust the regulator for the lower power if that is what your goal is, like for pesting in a barn or similar situation.
What do you think about this theory?
What is your experiences?
Some time ago I installed a power plenum on my pcp for the obvious purpose of shooting heavy pellets and slugs at higher speeds. After using it for a while I moved away from heavy pellets and especially slugs and use mostly 18gr pellets.
I then wanted to shoot light 14gr pellets at lower speeds but did not lower the regulator pressure. - Yes I know I should but it was set perfectly for 18gr which is my main pellets and I did not want to change it. - (EDIT - I should have said - I did adjust the hammer spring to a lower setting to get the best from the 14gr pellets.) What I experienced is that it would have a big extreme spread in speed. My theory is that once the regulator let air through to the power plenum, the air consumption per shot is to low for the plenum pressure to drop enough for the regulator to open after each shot. It takes a 5 shot cycle for the regulator to open again. Because of this the pressure and thus speed goes up and down and give vertical stringing. Once the regulator open, the speed is lower because of lower hammer, ,remember the regulator is set for 18gr at higher speed, and speed increases as the plenum pressure drop. Once the regulator open again the speed drop again. Speed confirmed by chronograph.
That is why one should have a smaller plenum and adjust the regulator for the lower power if that is what your goal is, like for pesting in a barn or similar situation.
What do you think about this theory?
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