Reply To: How much effect of a consistent regulator on accuracy?

Forums PCP Airguns How much effect of a consistent regulator on accuracy? Reply To: How much effect of a consistent regulator on accuracy?

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nervoustrig
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As RJ mentioned, the single best thing you can do is set up the tune so it is least sensitive to pressure variations.  Crank up the HST until the velocity no longer increases, and then dial it back until the velocity falls to about 97% of that maximum.  When set up in this manner, it is analagous to being at the peak of the bell curve of a traditional unregulated PCP:

The region represented by the box (dotted line) is where the velocity is quite stable despite spanning a pressure range of 2600psi down to 1900psi, or a change of 700psi / 48 bar.  So for example, you could take this rifle and regulate it at ~2250psi (the midpoint of that pressure range) and the regulator could vary 20 bar in either direction and have a negligible effect.

Granted, most regulated PCPs will not be so well balanced for whatever velocity we happen to pick as our goal.  This balance is a combination of pressure, porting, hammer weight, hammer stroke, hammer spring tension, and the valve return spring.  So if you really want to make a particular gun as agnostic as possible to pressure variations, you can start by tuning it as an unregulated rifle and manipulate those parameters for the broadest possible useful pressure range.

But unless something is wildly out of whack, it's probably not worth it.  Regulators afford us the luxury of being a bit sloppy.  They allow us to achieve good results even when things aren't optimally balanced.  And that's okay because hopefully we never have a regulator that is as erratic as the example I used.  So for the most part we can take the convenient shortcut of adjusting the HST to 97% of maximum velocity and promptly enjoy an extreme spread that is as good as can be expected when taking all the other factors into consideration…things such as variations within the pellets themselves and the repeatability of the hammer strike due to friction, subtle sear drag, etc.