20 Calibre saves a lot of hassle discuss

[angrybear]

While governed by the 12fpe law ALL calibres have to compromise on something.

.177 to be fast & flat must be light wt which reduces the energy the mass can carry so it loses momentum & terminal energy faster.
.22 due to the pellet mass hold's it's momentum & retains better terminal energy, but due to the limited muzzle energy has a far more pronounced trajectory curve.
.20 just happens to have a frontal area x mass that suits 12fpe far better than the others, giving a better BC, & terminal energy, So while it's still a compromise, as a sub 12 HUNTING pellet it's a better compromise than either one.

You only appreciate how good .20 really is when you actually go out & use it, in a properly set up rifle.

However once you remove the muzzle energy limit (FAC) .22 or .25 make more sense.