I have a 1902 rifle with a 1901 rear sight (my favorite of the bunch) but the lever/switch lock on the front of my rear sight is frozen.  If you imagine looking down from the top and the front sight is at 12 o'clock my lever lock is stuck at about 11 o'clock and hasn't ever moved since I've had the rifle.  I did wick some kroil to it but I don't know which way to encourage it to move. 

I'm assuming it's a lever lock with a cam surface underneath but I could be wrong about that!  I was shooting today and I needed to move it 4 moa (1 scribe notch) but it's immobile.

thanks in advance.