Sounds like the early LSA Tikka, the model prior to the M series.
The bolt cams open on a stud rather than an angle on the rear of the receiver and has more lift (90 degrees ?) than the 60 degrees of the M series which allows the lugs to contact more of the lug seat, well worth purchasing as they are a very nice rifle to use, the dovetails are 5/8" (16 mm), the current Sako Tikka optilock mount fits the older Tikka models as well.
Magazines are single stacked and turn up occasionally at usedguns.com.au.
HERE. 
