Italy is limited to 328 fps@0,20g (= 1 Joule).
This graph will show you that 0,25g BBs are slightly better here:
With 400 fps@0,20g (= 1,49 Joule) - this is what we use here,
0,25g BBs are also the best choice for range.
You can find lotso of other things and mythbreakers in the ATP:
For CQB (range max. 30m) I recommend 0,20g.