It's a high-quality, bolt action rifle, which apparently comes in .223 rem, .222, and a few other high-velocity, small-bore calibers. Sako is a Finnish firearms manufacturer.
You can find more information buy searching for Sako L461 on Gunbroker, or reading the Sako article on Wikipedia. A blue book of gun values can help you find the appropriate price value if you're looking to sell or insure your L461.
I have a sako L461 serial no 97578. This was purchased in 1968 , so, I guess no 86302 would be somewhat older.
Another Sako barrel
Someone at the Sako collector club might know.
You will have to contact Sako. Falls outside published data.
The twist rate is 14"
62 or so
No English book published with this information.
1-8 or 1-12
1/14 IIRC. Have it verified by a gunsmith
Need a DETAILED DESCRIPTION OF ALL MARKINGS to answer.
No known published sn data in the US
SN 128273 was shipped in 74 and SN 152027 was shipped in 78. Best estimate would be it was made in the 77/78 time frame.