The finnfire has quite a tight match chamber with little freebore, any slight build up of wax or lead can lead to this problem.
Keep clean.
What ammo are you using ? I had a problem with CCI subs, Winchester subs can be over waxed.
CCI recommends high velocity ammo is NOT used in this rifle.
PV.
Thanks for your response .The bolt had a layer of black gunge at the firing pin.Gave it a good clean and it seems to be working ok.The Sako is a P94S but i cannot find my original paper work to determine which model . I think its the light weight hunter .I have used stingers in the p