I have a 1925 and a 1943 Mosin. Both were made in the same factory but you can see some dramatic differences in the two with regard to how they were manufactured. In '43 the Russians were said to have cranked production up to close to 100,000 guns per week.
The '43 receiver markings are a lot more plain. Also, a lot of tool marks on barrel and receiver. The Russians had decided on a round receiver for easier production back in 1938. My '43 also turned out to have a split stock that I was working on repairing when I took the pictures.
The '25 has much nicer markings, and smoother machining.
A better view of how severe the tool marks are on the 1943 receiver. Also note that the side scalop is missing from the left side of the receiver, making it a "high wall" The stripper clip guide area is also only machined for ther essential slot for stripper clips. The tail of the receiver is also not tapered off on the sides like the 1925.
The 1925 model has a machined front sight ring, while the 1943 has a metal stamping that is welded to the sight base.
More stock markings on the 1925, and you can hardly see the stock repair to the heel from this side.
The 1925 also has stars stamped into the barrel bands, that the 1943 does not have.