M9 is the official United States Armed Forces
designation of the Beretta 92F pistol
which they adopted in 1985
to replace the legendary m1911
pistol in .45 ACP
won the contract because although SIG
was able to produce a pistol that met the requirements and sell it for a slightly lower price, Beretta
was able to have a better bid
for the price of spare parts
The choice of 9mmx19 in this new sidearm was mostly logistical as that was the standard NATO pistol round, it continues to be so to this day.
Read more about this wonderful handgun here.