I know this may cause a bit if a stooshie on here, but came across this on utube.
First video had me really sceptical, as the reaction from the sheep was not great. Second video confirms it, the airgun is clearly underpowered compared to a CF rifle as the bullet it fires does not expand or mushroom in the slightest, which can be seen when removed from the animal.
Its stuff like this that suggests the minimum MV/bullet weight/calibre restrictions we have in the UK are perhaps a good thing.
The 175grn bullets are doing around 800fps. Similar to a handgun. I would think head shots would be fine, but body shots don't seem that devastating.
I just don't get the need or desire to start playing about with an air gun for hunting.....