Only conjecture on my part but I'm sure demand for rifles chambered in the current service cartridge of the time and country of use played into it.....i.e. .30 Army/U.S. and then .30 Gov't '06 in the States and .303 British for Canadian and British Empire sportsmen. Probably had more to do with ammo availability in the area of use than ballistics. I have seen a few '95 rifles so chambered but never a carbine.
I was told that my .303 M-95 carbine came out of Quebec, probably via a French-Canadian employee of the Brown Company paper mill in Berlin, NH. I bought it at Ray's Gun Shop in Milan, NH, around 50 years ago. I have the bill of sale somewhere, IIRC I bought some 180 grain Remington factory loads from Ray's to go with the rifle. It has a lot of blue wear on the bottom of the receiver and spots on the top of the barrel and on top of the tang, probably where is rested in a horizontal gun rack, but no pitting and no after-market holes. It is the only M-95 in .303 that I've recall having seen.