I have looked at the specification for the Gamo P-23. With a .177 (say 8.2 grains) pellet at 400 ft/sec the Energy (ft-lbs) is only 2.91. This is unacceptable to hunt rabbits or squirrels with. The minimum Energy (ft-lbs) should be at least 10-12 minimum. A more acceptable energy requirement for a clean kill should be greater than than the minimum I have quoted here. As the P-23 is a CO2 pistol, the pistol does not have unlimited usage unless you have a stock of 12gm CO2 cartridges. A more acceptable and useful air powered rifle would be something along the lines of the Air Arms S410 TDR



Export (FAC) versions should go up to more than 30 ft-lbs. A firearms certificate (FAC) is required in the UK for air rifles over 12ft lbs. I know, I know. But these weapons can be lethal even for humans above 12 ft-lbs.