Not sure where you can get them, but here is how I solved the same problem in my Savage. I changed out the O-rings and then put some smaller washers over the O-rings then the big ones (that are warped like yours). No more leaks. Just make sure the smaller washers/shims you use fit snug around the cup shaft and fully cover the O-ring. I used some washers/shims I had in an Ofna shim kit.