LAst months American rifleman magazine had good article on the M17/M18 Pistol and ammunition. The Competition didnt specify the caliber and sig stayed with the 9x19. They went to Olin/Winchester for the ammunition. two loads a M1152 Ball 155gr FMJFP (Flat Point) and M1153 special purpose - Controlled expansion 147 grain JHP (based on Winchester Ranger T Law enforcement design) . Additionally M1156 plated drilled dummy and M1157 Blank. The first two have pressures of 39,700 psi (+P at least). Winchester has contract for 400,000 rounds to start. According to win article they have already delivered over 20,000 rounds. What got my attention is the 155 grain FMJ vesus a 124 FMJ like Nato std. MAy have something to do wityh specific requirements. Looking at teh First 9x19 TRC FMJ bullets they we8ighed 124 grains. In WW 2 with changing designs to conserve scarce materials weights went to 115-116 the around 92 with Sintered bullets. All worked. Since 1902 much has happened in 9x19 bullet designs. When I shoot my P08 or P38 pistols I use WIN 115gr FMJ in white bulk box. These have proved reliable and dont overload these old pistols. Looking at Modern Ammo, the FBI recently adopted a 135 grain controlled expansion JHP. Whatever the reasons designs keep evolving. .