In one of the forums, the question came up if 120 Joules is achievable with a slingshot.
I do not think a hand held slingshot can do that. Especially not in countries like my otherwise beloved Germany, where wrist braces are illegal. The maximum energy I ever achieved was 78 Joules, and that is only possible on a warm, humid day with some luck.
Reliably, 65 Joules are possible for me, but that is far away from 120 Joules.
So the idea is to build a foot operated slingshot. Me lying down with the feet against the "fork", and pulling the pouch with my trusted self made release, held in both hands.
I plan to use two stretches of Thera Band Gold per side, tapering from 14 cm to 7 cm. That will average one full Thera Band gold. At 550%, this would be 80 pounds per side, 160 lbs total draw force.
I got these values from extrapolation of this table:
I know I can do that from the gym rowing machine, where I pull 135 kg (that is all they have).
We will see!