I've never found any 9 MM cases I've checked to have grown enough after repeated reloading that required me to trim them because it exceeded max OAL. If anything, it might shrink a little. But, I have found that both 357 and 44 mag, when loaded with high power loads, will grow enough to require a trim after several loadings. So yes, I have trimmed pistol cases, but only straight wall, rimmed, high pressure cases such as 357 Mag and Max and 44 Mag. And every once in a while I will trim them if I'm starting to get significant variance in a lot of cases on OAL just so I have a more uniform roll crimp on them. Variations in OAL length definitely comes into play with roll crimped cases.