I have a crossman 10 pump. Not sure of the model but its a bolt action single shot. Will kill a rat clean. I killed a opossum with it, but it took in the area of 5 shots. Either way opossum didnt eat any more duck eggs.
Check out the higher end ones like the beeman single pump. Deadly accurate and about 800fps with one pump.
Concentrated power is not rendered harmless by the good intentions of those who create it.