Pughs, thanks so much for the fast reply. The man in the center of the photo, with his hand in his pocket is my great-great grandfather Wylie Pollard. He was sheriff of Potter county Texas from 1924-1929 (you can just see his badge). I have tracked down the "Tomey Chisum Distribution" and found out that it was located at 11th and Polk street in Amarillo, Texas. I've also found photos which confirm the location. Maybe the Stutze AA was used by the sheriff's office because of its speed, maybe these are Pollard's deputies. Pollard died in 1931, so this photo must be after 1926 but before 1931.