The Slingshot Channel tests the three fantastic models made by Perry Adkisson from out of California. The PS1, PS2 and PS3 models arrived with different band sets (all interchangeable). Therefore, the slingshots are tested with the Chrony. The strongest one shot a 15 mm steel ball at 69 m/s or 225 fps! That is almost 250 km/h.
Perry's website can be found here:
Here is the video review: