Original caption:
Women’s machine gun squad police reserves, New York City. Practicing with Lewis Machine Gun which is to be sent to the front. The killing range of this gun is 2 miles and it fires 500 shots per minute. Captain Elise Reniger, manning the gun, Miss Helen M. Striffler on the rear seat, and Mrs. Ivan Farasoff driving.
Dated 08/01/1918 (d/m/y)
Don’t worry they didn’t get ammo /s
Though seriously it is a very thin pole plus why is it so long.
That looks like either a mobile AA setup, or they’re training to use it for indirect fire. The thing I note is how high she’s aiming and that’s what makes the most sense to me.
Indirect fire is the less likely of the two options, since 1918 is pretty late in the war (they’d gotten the hang of proper artillery by that point instead of MGs for indirect fire). This actually looks like a pretty mobile little AA station.