I had a few problems with my CM9 (fte, ftl) in the firs 50 rounds and a couple in the next 50 and none after the recommended 200 shot break-in period. Follow the prep guide, lub it, rack the slide a few hundred times, field strip it again and look for anything out of the ordinary wear (you may see some small wear on the plastic guide rails), lube the slide again. I found that the S&B ammo which was my 2nd hundred shots worked much better, probably due to the increased velocity.

Sellier & Bellot : 9mm 115 GR FMJ Muzzle Velocity : 1280 fps
Federal Range & Target : 9mm 115 GR FMJ Muzzle Velocity : 1180 fps
PMC Bronze : 9mm 115 GR FMJ Muzzle Velocity : 1150 fps
PRVI Partisan : 9mm 115 GR FMJ Muzzle Velocity : 1148 fps

After the S&B, Magtech was almost as accurate and with no problems, but I don't know the velocity.
For defense loads, Gold Dot Short Barrel & Critical Defense worked very well.

Good luck.