Deleted member 1487
The French experimented with a 6mm semi-auto rifle/fully automatic rifle weapon system in 1900, but ultimately didn't decide to invest in the system or develop it for a variety of reason.
It seems the system had promise, because it eventually would lead to the MAS-49 rifle using the same gas system. For the sake of argument the French retain the 8mm Lebel for the Hotchkiss machine gun, but use the 6mmx60mm round for infantry rifles and automatic rifles. What sort of impact would that have on the fighting in 1914 and the response of other nations leading up to WW1?
Note that having such a weapon system would give the French a huge firepower advantage in infantry combat relative to nations with bolt action rifles and only heavy MGs, while also butterflying the Chauchat.