I was an Army MP in the early to mid 1980's and I carried a 1911A1. Female MP's carried Model-10s or Ruger Speed/Service Six's in .38 Special. MPI (Military Police Investigators) had 2 inch Model-10s or Model-12's. The Beretta M9 was adopted about halfway through my enlistment, but I never saw one. They went to deployable units (82nd Airborne, 101st, etc.) first.