Photo Library | FBI

F.B.I. Agents firing Model of 1928 Thompsons at their range in Quantico, Virginia. The F.B.I. gun vault at Quantico, Virginia.

Note the preponderance of Remington Model 81 Police Rifles (two rows in left cabinet and one more row behind Thompsons in center cabinet).
Eleven Model of 1928 Thompsons are visible in the front row of the center cabinet, plus one more in pieces mounted on a training board (above right rack), and one more with a "L" drum (at top right).