What is it that makes some spring pistols so pellet fussy?
I’m guessing it’s something to do with different weights sizes and shapes exiting the barrel at different points in the shot cycle?

I’ve been pellet testing quite a few pistols at home, prior to then zeroing at 10 yds (length of my hallway)

I usually test Bisley practice, AA Field and JSB express and one will always group tighter than the others. Recently been adding Accuracy plus to the test for some very low powered pistols.

You have to be a half decent shot in the first place to get decent enough groups to tell which pellet is best.
It’s quite knackering doing that with a two handed standing hold for long periods, and often I’ll narrow it down to two pellets and then have to come back to it later as arms and eyes get a bit tired and it’s diminishing returns to carry on.

It’s worth the effort though and I always enjoy the moment when you’ve got used to them, they are finally zeroed in, with the right pellet and what seemed like an inaccurate and untameable little beast suddenly starts behaving itself putting the pellets in a nice little group.

Cheers,
Matt