I would use Kintex Silver - very fast fitness rubber bands.
It propels 8mm steel well over 130m/s with some tapering.
I suppose that I will just have to adapt to the weight of 12mm steel
and use about 3,2x the bands for the 8mm steel setup and I should achieve the same velocities, right?
I need quick help, with which tapering I could start experimenting to get "high speed".
I have seshou guru 0,75 and 1,0 and GZK Green 0,66.
For these bands each, which tapering shall I use to get 400 fps or more ?
At full butterfly I have 156cm (61,5 inches) draw, which I want to use.