I recommend Federal HST 124 gr. or Speer Gold Dot--both have been extolled on the forum as excellent R9 ammo choices. I would avoid Remington or any other cheap ammo choices. Basically, just stick with what works. Speer Lawman is an excellent range ammo with similar ballistics to Gold Dot. Also, stay away from any ammo with hard primers such as Hornaday or foreign ammo. Winchester, Speer, and Federal all make their own primers that work well in small striker fired pistols. Hard primers can cause light strikes or misfires in the R9.