I usually trim the cases for semi-auto pistols once
by Lee J. 
, hagerman,NM, Wednesday, September 25, 2013, 21:34 (4020 days ago) @ Hobie
When I first moved to NM in 1975, I left some 9,000 Super Vel 9 MM Parabellum cases lying in the sandhills East of Roswell when shooting Jack's. They just were not worth trying to find after shooting in the field much less trimming.
If you measure enough 9mm cases of various brands and lots you will see there is no uniform length change.
This will depend more on case hardness gradient due to heat treat in manufacture, which also varies between manufacturers. Enough to drive the handloaded wild. Too many other variables will effect accuracy. In a laboratory setting the 9mm can be made quite accurate, however the 9mm Parabellum has never been known as a match cartridge. 
Complete thread:
- Reloading -
Art,
2013-09-25, 19:18
![[*]](themes/default/images/complete_thread.png "Open whole thread")
- JimT did an article - Paul, 2013-09-25, 19:58
- I usually trim the cases for semi-auto pistols once -
Hobie,
2013-09-25, 21:25
- I've been reloading since I was a little kid (literally) -
cas,
2013-09-25, 21:28
- I've been reloading since I was a little kid (literally) -
Lee J.,
2013-09-25, 21:53
- I've been reloading since I was a little kid (literally) - Art, 2013-09-26, 06:52
- I've been reloading since I was a little kid (literally) -
Lee J.,
2013-09-25, 21:53
- I usually trim the cases for semi-auto pistols once - Lee J., 2013-09-25, 21:34
- I've been reloading since I was a little kid (literally) -
cas,
2013-09-25, 21:28
- Reloading -
Lee J.,
2013-09-25, 21:25
- Reloading - Bud, 2013-09-26, 08:08
- Triming handgun cases - Charles, 2013-09-26, 10:46
- I've never trimmed a 9mmP case.... - JD, 2013-09-26, 14:35
- I once did some experimenting with 9mm lengths.... - Harry O-1, 2013-09-27, 07:51
- Been reloading for years . . . - Kentucky, 2013-09-27, 09:18