To qualify my previous post a little, so much depends on how much time you have and how much importance you place on the power output being similar with a wide range of pellets and differing weights. For those willing to experiment and devote the time, we're playing with factors like transfer port diameter, piston weight, piston momentum, spring rate / force / preload, piston seal fit etc. Is a rifle that is "balanced" to shoot different weight pellets at similar energy levels any better than one that doesn't? To my mind, no. There can only ever be one truly 100% perfect individual set-up between rifle and pellet and, to my mind, we accept the compromise when it comes to differing performance with different pellets. As I'm sure you do, I'd always put far more emphasis on accuracy.