Some American airgunners have actually reduced the power of their springers to around the 12fpe level, because their guns are nicer to shoot and more accurate at that power.
These are mainly target shooters, it is true.
I see no problem with say 14 fpe, but, personally, I wouldn't want to shoot a 20 fpe springer.
They must make your teeth rattle, and they don't actually take the accuracy range that much further out. Perhaps about 10-15 yards.
If you want more, better to go rimfire, which is easy to get in the USA, but not so easy here.
Don't get me wrong. I hate government imposing limits.
I wish we had American gun laws here.
However, a spring piston air rifle is still a springer, and a springer functions better at lower power.
Arthur
I wish I was in the land of cotton.