If the restriction of the depinger is severe, then the placement of it would determine the plenum volume.... Reducing plenum size results in a reduction in the maximum power the gun can make, and also reduces the efficiency when you approach that power level.... What you are doing is forcing a pressure drop during the shot.... There are two other common methods used to reduce the power (without changing the fill pressure).... You can strangle up the transfer port, which generally reduces the power and increases the shot count, while leaving the efficiency about the same.... It tends to reduce the ES and flatten the bell curve in an unregulated PCP.... Alternately, you can reduce the dwell, which reduces the power and increases the shot count while usually increasing the efficiency at the same time.... However, on the first half of the bell curve, it can increase the ES....If you are dealing with an unregulated PCP, you are already dealing with an ES of several percent, compared to a regulated PCP.... If you shoot at 50 yards and less, then a 4% ES will be fine.... At 100 yards, you should strive to get the ES down to about 2% or you may notice a change in vertical POI.... Generally, in an unregulated PCP, the ES from shot to shot is well within the ES of the bell curve.... For example, if you are tuning for a 4% ES over the shot string, the ES on the front (HP) side will seldom be more than 2%, with the velocity from shot to shot staying within the total ES of the string.... If I have an unregulated PCP that I wish to detune, my usual method is to reduce the hammer strike AND the fill pressure.... This will reduce the FPE and the noise, while increasing the shot count and usually the overall efficiency.... I usually leave the transfer port alone, unless I am going for drastically less power.... Purposely restricting the flow INTO the valve (eg. with a small hole in a depinger) would not even be on my radar....Bob
Hi Mike, If you could make the first shot faster that would help toward having a flatter string, and the velocities do not have to decline. As in your example you should be able to get five shots about the average velocity of your string. hth.