A friend found these photos of an ancestor in the (presumably US) military around 1912.
Any thoughts on getting an exact year or more details such as unit or location?
(Looking more closely at that last one they are lucky they took this in pre-social media days, I’m sure posting that kind of gun safety online while in uniform would result in disciplinary action 
)
Clues from the displayed firearms: rifle appears to be an M1903, which was in Infantry service from 1903 to 1936. The pistol is an M1911, in service from 1911 to 1985 as a standard sidearm.
So, from 1911 to 1936. The uniforms suggest to me the earlier end of that time range.
Bolt action rifle and moreso the almost wagon wheels on the truck look like it could be pre-WWI to maybe 1925 to me.
The OP already has a rough date of 1912.
If all of the pictures are from the same year, it is later than 1912. The Series 2 Liberty truck in the third photo did not enter service until 1918.
Seems WWI era to me so I’d guess 1917-1919.
So, the American Expeditionary Force (maybe?).
Where’s the pistol?
The last photo, being irresponsibly wielded at his comrades. Classic violation of “don’t point it at something you don’t want to kill”
Ah…I see it now (I had to enlarge the image).
Thanks.
Without insignia I doubt we can guess what unit it was and I don’t think there is enough detail to suggest a location either (they seem different places too).
I’m not terribly conversant with military history, but the fact that they’re wearing what appear to be gaiters (rather than puttees) in the third photo would suggest late WWI or after.
In the last photo, the goofball in the barracks cover is wearing 1910 leggings; the two in campaign hats are in 1916 dismounted branches leggings. Patch pockets replaced bellows pockets on the tunics after 1912.
