These are rimmed pistol calibre rounds measuring about 9x26R, what are they?
These are .38 Colt Army cartridges (.38 Long Colt, Inside Lubricated).
Here are side views, if anybody cares.
Was .38 LC ammo used by the military made at FA, or were there any made under contract by Winchester, UMC, etc.?
The .38 Long Colt Cartridge was made for the military by at least the following companies:
Winchester Repeating Arms Company (W.R.A.Co.)
Peters Cartridge Company (P.C.CO.
United States Cartridge Company (U.S.C.CO.)
Remington-Union Metallic Cartridge Company (REM-UMC)
Western Cartridge Company (W.C.Co.)
Frankford Arsenal (F. A.)
The initials after the names are what appeared on the dated headstamps.
It is likely that Union Metallic Cartridge Company made some also, before the merger with Remington. They are mentioned as having made the Navy version, at least.
U.S. Cartridge Company made some with an undated headstamp of “U.S. 38 COLT NAVY.” Production probably began about 1888 and had an outside-lubricated bullet. Production of that type ended in 1897 in favor of the inside-lubricated Army type cartridge.
Reference: HWS Volume I (1st Edition) pages 3 - 9)