I don't claim to be an expert in guns, but are you sure it's a drilling?
I.e. it has three barrels? And if so, that it actually is a Tikka?

I know a fair amount about the Finnish made guns, but have _never_ come across a Tikka drilling, and a mention of such a special weapon would for sure have been made in Arma Fennica.
If such a gun did, indeed, exist, it would be worth a fair deal of money on rarity alone.