Most cities had their local loaders that did provided ammunition put up in NPEs from the big companies, Winchester, Union Metallic Cartridge Co., Western Cartridge Co., and U.S. Cartridge Co. In California in addition to Selby they also had California Powder Works, In Oregon the big one was Honeyman Hardware in Portland. I don't recall the Seattle names as I'm on the road, but in Spokane it was Ware Bros. Here is a 1901 REPEATER No. 10 loaded by them --
1901 No. 10 Ware Bros.jpg
From 1901 until just after WW-I, Winchester headstamped their NPEs 1901 and the cases they loaded themselves WINCHESTER or WRA.
Similarly, UMC used different names on their NPEs than on their factory loaded shells --
UMC UNION NPEs 1901.png
UMC UNION No. 10 NPE.jpg
UMC EXPERT NPEs 1901.png