I have no experience with the 25, but this issue seems to come up a lot on Savage rimfires that come with bases, so I'd say whatever company produces Savage's bases leaves a lot to be desired.

Like I mentioned, I have no experience with your model rifle, but if the bases for the front and rear are the same, try taking them off and switching them; back one to the front and front one to the back.

Also, I used to have issues like yours with various brands of rifles until I started using either 1pc Picatinny rails or Burris Dual Dovetail bases and the corresponding Signature rings. I've started using 1pc Picatinny rails and quality rings on just about everything, and now it's very rare I ever need more than 5 MOA in any direction to get a 200yd zero.