I think it is illegal.
A lot of sticks could KO in one blow.
Those ice hammer/axe for mountaineering for sure one shot kills.
I think the problem is not the hit ...
Rather, it is the punch, i.e. how many J we're talking about when it release to extend to it's full length ?
I don't have a clue ...
But I'm sure if the victim is back against the wall when his chest was receiving that punch ... minimum break some ribs if not punch a hole thru !!
Another consideration is, it's sole purpose is as a weapon with none other purpose whatsoever.
Just like low grade pepper spray ... if "she" got one, "she" might get away even in court.
If "he" got one, likely be illegal.
But if it's high grade one, likely even "she" would get into trouble.
Another example is, it may be ok if you own a fire engine ... the worst it could be ... you could never get a license to drive it down the road legally.
But if you have an "anti-riot water canon" ... I think you're in trouble.
