I know this has come up before, but I don't think there was a consensus!
The model guns in the pics below are from Strelets Russo-Turkish War range. I am wondering if they could be useful for WW1.
Could this Russian Mountain Gun be a French Schneider Mountain Gun (I think Schneider sold a lot of guns to Russia; but maybe that was after the Russo-Japanese War):
The Russians built their own versions of Krupp Guns but using Bronze instead of steel as a result during the Russo Turkish war many failed under heavy use. I think the mountain gun like the field piece is based on Krupp type guns but other then that I cant say exactly which, but maybe a russian version of the Krupp 6cm Gebirgsgeschütze circa 1870.
The lower gun is probably meant to represent a very early Krupp(C64ish) as I believe the later models had a reinforced barrel making them somewhat thicker with a step just forward of the trunnions to the breech see here:
I was thinking of either older guns in Africa or older guns in Ottoman service. But it seems the models are probably not worth the expense (about $10 per box).
I think the Russian mountain gun you posted, is in fact quite similar to the bronze mountain guns used by second-line Japanese troop during Russo-Japanese war.