I `ve made some high speed, medium and target bands for Joseph from France.
Tested the stuff with 11 mm steel and some chrony and coconut shots. Up to 96 m/s; 315 fps.
These bands are VERY easy to pull and the fastest band can easily penetrate a coconut with only 10,5 mm steel.
But surely better with11 mm.
Here is the nice video:
Have fun shooting, Joseph!!
And all the other slingshooters - have fun watching!