The weapon we recommend to humanely dispatch mink is a 0.22 (or 0.177) air rifle with a power greater than 8 ft lbs but less than 12 ft lbs; above this power a Firearms Certificate is required. If a rifle is being purchased specifically for the purpose of mink control a rifle towards the top of this range is preferable, as this would allow some decline in performance over time but still retain ample power to achieve a clean dispatch. The weapon should not have a sound moderator as this makes it difficult to put through the cage mesh. Equally, if used solely for humane dispatch, the front sight could also be removed to avoid catching in the cage mesh.
Air rifles powered by a range of methods can be used, provided they are in the appropriate power range. However, a spring loaded or gas ram powered air rifle will probably be the most appropriate if the weapon is primarily to be used for humane dispatch. The disadvantage of CO2 powered rifles is that once a cylinder is started it should be used within a relatively short time. If mink are to be dispatched only occasionally this can lead to a waste of gas.
If an older air rifle is being used, where there might be concern over its power, we recommend that you have the power tested using a chronograph. Many gun shops will provide this service.
Pellets of any type may be used in air rifles of the recommended power, although those designed for hunting and pest control would be ideal. You should check all pellets before they are used to ensure that they have not been damaged.
Other published advice recommends the use of an air pistol in conjunction with ‘Prometheus’ pellets and combs to restrain the mink at the end of the trap while it is shot. However, these pellets are not always available and other pellets do not achieve the same penetration when fired from a pistol (these are limited to 6 ft lbs). Suitable air pistols are also not widely held by volunteers. Consequently, the WRT recommendation above is for a more robust procedure that will reliably dispatch mink using a range of pellets, and weapons that are widely available.