Shooting rats

I don't really have the patience to shoot rats this time of year. However, my messy feed grinding operation has attracted them.  I shot two yesterday and then ran out of ammo and had to change brands. This new .22 ammunition shoots all over the place. I've never been real precise. I go for the if you can't hit it the first time you've got 10 more chances school of shooting and so I sight the scope in if I drop the gun or the bolts come loose. This new ammunition shoots completely differently. I don't see how an obviously lower powered ammunition can shoot high but it does. I went back to some good CCI's and I was shooting right on the cross hairs. The new Federal ammo I have to aim low.
I took a photo. It is an old Weaver K1 or K2. Not sure the model number. It is older than the famous K-4. It is mounted on an old Ruger 10-22. It is fun to shoot. I missed four times today. I tried a starling and shot out all his tail feathers and sent the powerline vibrating like crazy. Perhaps I'll have to go back to the 12 gauge. It is kind of loud...