I use WWB 115 FMJ's quite a bit .. also in my second R9 have been putting some Bosnian made ''Igman'' 124's thru .... very successfully.
Other 115's that seem pretty OK are the S&B FMJ's.
I do tho expect the occasional malfunction with ball ammo - pretty rare for me but - can happen. For practice I find this no problem, plus - I am ever more getting to stage where I am not keen to punish the gun unnecessarily. It's not a plinker and I just need to know it's reliable ... which for me with GD's it sure is.
I have put 50 rounds thru my new one ... and just cleaned it and lubed ... it is now stoked as carry and will probably wait a while before firing off a mag full of SD ammo .... and that'll be it .. no special extra clean ...... just test and carry.
Back to ball tho - IMO perfectly adequate for practice .... even allowing for odd malfunction.... and I think 115's should cut it pretty much OK along with 124's.