Army, as I recollect, wanted a replacement for the Colt SAA in 45 LC. Troops in one of the turn of the century US conflicts (Philippine - Am War) were finding that the smaller calibers (38 Long Colt) were not getting the job done.
Luger submitted the "American Eagle" -- 1900. I had one at one point in my collection. (Got seriously burned on this item.) The Luger was 7.65 mm, "30 cal. Luger."
Colt was producing some semi-autos -- Mod. 1903, in 32 ACP. Mod. 1908 went to .380 ACP.
Wiki has a pretty complete article --
I carried one of these (M1911A1) around in the Army. The guns issued were not particularly closely tracked by the Armorer and Supply Room. We didn't check them in and out like the M-14. Could have very easily packed one in the duffel and taken it home on leave. Many did, and I see US military issue 1911 in drawers and attics now and then.
Army issue 1911 was notoriously loose. They rattled. "Impossible to hit the broad side of a barn with one if you were standing inside." 230 gr. FMJ ammo and sloooooooow velocity, resulting in a really loopy trajectory. Pretty much hopeless for hitting anything much beyond 50 ft.
This performance was the reason I never packed one home on leave.
But I own two of them now, Springfield. They're tight, accurate, and the ammo is much, much improved.