Rubuta ci gaba don wannan sakin layi - Gregory ya isa San Diego Marine Corps Base a watan Yunin 1927 kuma ya yi aiki a matsayin mai kula da gidan har zuwa Disamba 1928, lokacin da ya yi tafiya a karo na biyu na aikin bincike a Nicaragua. An haɗa shi da Brigade na Marine na Biyu a ƙarƙashin Birgediya Janar Logan Feland kuma ya yi aiki a matsayin mataimakin mai kula da brigade har sai an canza shi a matsayin mai kula da "Guardia Nacional de Nicaragua". A wannan matsayin, ya taimaka a aikin agaji da ya shafi girgizar ƙasa a Managua a Maris 1931
kuma sakataren sojan ruwa da kuma kungiyar Red Cross sun yaba masa. Ya sami lambar yabo ta Shugaban kasa ta Nicaragua tare da tauraron zinare da kuma lambar yabo tare da tauraron azurfa don hidimarsa a Nicaragua.