My count is now up to 14, a combination of traps and air rifle. Got to say it is good practice with the air rifle, pretty much the same as Hog or Deer hunting, just on a smaller scale.
Gamo Expander .177 pellet. Advertised to expand with an air pistol as low as 3 joules. Seems to work well with my 7.5 joule air rifle.
I still have seven pellet types to test. I'm looking for the most reliable Rat killer.