Rubuta ci gaba don wannan sakin layi - A shekara ta 1906, Amurka ta kimanta wasu bindigogi na atomatik na gida da na kasashen waje, ciki har da Colt M1900, Steyr Mannlicher M1894, da kuma shigarwa daga Mauser. Kodayake Springfield Armory a baya ya sayi bindigogi na Parabellum na 7.65x21mm don gwaje-gwaje biyu daban-daban a cikin 1900 da 1902, hukumomin Amurka sun ƙi harsashi na 7.65x21mm a matsayin wanda ba shi da ƙarfi don amfani da soja. A cikin 1904, an gwada ƙananan adadin bindigogi na Parabellum a cikin sabon, mafi ƙarfin 9 × 19mm, amma hukumomin Amurka sun sake ƙi bindigar. A wannan lokacin, rahotanni da yawa na gwagwarmayar gwagwarmaya game da rashin isasshen ikon dakatar da bindigogi na Colt.38 na sojojin da aka yi amfani da su a cikin 1899-1902 Philippine Insurrection
da kuma binciken da aka buga na ma'aikatan Sojojin Amurka da aka samu daga Gwajin Thompson-LaGarde ya haifar da buƙatar bindigar soja a cikin.45 (11.25mm).