My goal is much more modest; 200 fps with 175 grain lead. The limiting factor in my case is my own physical strength. I want to do it with a standard configuration fork and normal draw. Though I've made good gains so far, building upper body strength at my age (68) is not as easy as it used to be.

Good luck with your quest.

 

That is just way way too fast, if it should get out of control, that's it someone or something is going down.

 

160-170 fps with .53 lead ammo (220gr)(14g)

Currently .38 is giving me approx 6-7 fpe. With stronger bands and heavier ammo I'm hoping to hit 12 fpe +

 

.45cal at 400fps from a slingshot would be very good. It could be used for home protection. If someone is trying to break into your house and they are shot in the head or chest they will stop what they are doing.

 

I have mislaid my rotary cutter and don't have any black Theraband at the moment so the 400 fps attempt will have to wait. In the meantime I've done some work with the "Heavy Stuff" and have actually beaten my previous best KE.

Heated Silver Thera tube
30 inch fork extension (wrist brace essential)
1700 grain lead ball
158.9 fps
95 ft/lbs
129 joules

I also have a high speed camera now. Bottles, fruit, cans, coconuts - watch out!