Any fmj 32 automatic ammo. Hollow points are a waste of time. Ball feeds and penetrates 21" to reach vitals. Pocket gun cals. 22,25,32and 380 are best in FMJ ball ammo. 9mm and up hollow points work. I use S and B ball,Geco and PPU ball in my Colt 1903 a d F.N. 1900. John browning knew what he was doing.