What you are experiencing is the result of your rifle having the original 1 piece spring. The firing pin spring has a tail that retains the cocking piece pin, thus making the whole spring rotate when cocked. The sharp edge on the end of the spring will dig into the bolt assembly screw when the bolt is turned down, essentually "unwinding' it. This wants to lift the bolt in resistance.
The fix is to either get the 3 piece upgraded spring from Savage, or you can polish the end of the spring and grease it.