"Si-marked" (?) Finnish Mosin Nagant

Hey all,
I have owned a few Finnish-marked (i.e. boxed SA) MN rifles, but came across one today with an Si mark. I cannot find anything about it online (but I get lots of hits with Mosin and Russia). I have posted pictures of the receiver markings, but you'll see the Si mark (S i 7103) on the lower left rear of receiver (rightmost picture). Anyone know what it means?

Thanks,
Chris

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Ah. Excellent question. That mark was put there by the importer and is the rifle serial number. The SI is the translation of the Russian letters. You can also see them above the serial number on the barrel. Good example of a Finn capture rifle.