A regulator is a device that lowers the air pressure of the reservoir to an ideal level before making it available to the firing valve in your air rifle. It sits in the reservoir in front of the firing valve and it regulates the air pressure going into the valve when the trigger is pulled.
A firing valve in a PCP does not operate at its peak at 3,000 psi – not even close. Most of them work best down around 2,000 psi and some work best at even lower pressure. But, the fact is that they still do work acceptably well at higher pressure. So, the rifle gives a string of shots at a more or less constant velocity until it drops below the lowest pressure at which the valve functions well.
Because the pressure is always the same, a gun with a regulator shoots with very consistent velocity, plus it may get a few more shots on a fill. As long as there’s enough pressure in the reservoir, it operates as described. When the reservoir pressure drops below the regulated pressure, the regulator remains open all the time and the gun becomes unregulated. It continues to fire, although you may notice a change in the discharge noise.
But you have to ask yourself if it’s worth a couple extra shots and a slightly tighter velocity variation to go to the trouble of installing a regulator? Typically regulated air guns are slightly more expensive to buy, or buying a regulator to fit to your rifle could cost from £150+. And as with anything that has more parts, servicing is slightly more complex and therefore slightly more expensive.
However, on the plus side, as a regulator is more air efficient you can get a higher number of shots per fill. And because the pressure going through the valve is always the same, a rifle with a regulator will shoot at a very consistent velocity and therefore will produce a constant POI, as long as there’s enough pressure left in the reservoir.
So on balance, we think… why not? If air rifling is your sport, why not go for the best performance? As long as you don’t continue to blame the rifle for your personal bad shooting days!