I have no particular interest in debating the merits (or otherwise) of hunting with catapaults.
The one thing I will say though is that the idea that 18ft lbs of energy is sufficient to ensure a kill in a non-lethal zone and without a well aimed shot is very, very odd to me.
Whilst this may appear to be "half as much again as basic air rifle", I will invite a different comparison.
Lets try "one fifth as much as a .22 rimfire cartridge....with an absolutley rubbish comparable ballistic coefficient". A .22LR rimfire round imparts about 100 ftlbs of energy. Granted it has different terminal ballistics than a .44 ball, however the idea that "a hit = a kill" on a .22LR is clearly nonsense. I cannot see how a round carrying less than 20% of the power, with lower range and less accuracy would impart such certainty.
As I said, I have no particular interest in the merits or otherwise of catapault hunting, however, I can. with some assurance, state that a hit in a non lethal zone, using a .44 ball carry 18ft lb of energy (and bearing in mind this energy decays FAST over range) would not necessarily equal despatched prey.
Red
Hence the need fr out and out accuracy, as best as possible and if you are ethical about your quarries' killing then you need to be on top of your game to use this method. At ten yards though, I would bet that a heavy lead ball that is shifting with more force and power than a dinky little pellet will do the job just fine. I've said pretty much all I want to say on the matter now, I think it is up to the individuals personal beliefs what they do, if they are happy to leave animals winged and maimed and have a clear conscience, then good for them. I prefer to be slightly more clinical in my methods of killing.