I just bought the bsa red dot sight for 49.99 at Big 5,and I like the results. Very easy to sight in and use. I'm shooting some small groups at 12 yards,that should get rid of the rats. This is the same sight that comes with the Gamo Shadow 1000,but I would not try it on the Kodiak.
The sight probably is not that grate when shooting out of 20 yards,to get the best is to get a UltraDot($120) but for me its fine.
:-)