IMHO - This photograph shows different aspects of the U. S. Third Cavalry uniform. It has captured men of "Troop B", that are off-duty, getting ready for duty, or just coming off of duty.

The men 'with brass buttons' are wearing their 'Five-Button' uniform jacket, some with a white Dress-Shirt. The blue wool shirt, being worn by the other men, is the Fatigue shirt.

All the men have trouser stripes. We just can't see some of them.

Some of the men are wearing the model 1895 Kepi. One man is wearing a campaign hat. Other men are without head-gear.

To the left, in the picture, are 'lockers'. On top of the lockers are what appear to be 'covered' Spiked Dress-Helmets, as well as campaign hats. The Kepi is likely kept in the locker.

The leggings were not worn at all times. Given the construction of the room interior, the photo was most likely taken in a barracks in the U.S.A.

Some sources place Troop "B", 3rd U. S. Cavalry at Ft. Myer (Arlington, Va.), during part of 1899-1900, and in Wyoming, in 1902, upon returning from Luzon, P.I.

Neat photograph of racked model 1896 or 1898 carbines showing lots of barracks details! (The Magazine-Gates appear square-cornered and Boxy, which suggests model 1898 carbines. I like the padlocks on the rack and the cloth case on at least one carbine).