It is now a reality - cost me 12 hours in the shop today. A full size version of my pencil shooter! You strap it on like a "monster dildo of death". :wink:
In the pic, you see it next to the pencil shooter, it's tiny little brother. Gives you an idea about the dimension.
Attached to your chest, you can draw it back in a rowing fashion. This allows really high draw weights, impossible with a handheld slingshot. This is the most dangerous and effective weapon I have ever build.
45 kg (100 lbs) of a draw weight means it propels the 115 Gramm (a half pound) aluminum bolt, 15mm (0.59") diameter, with a 12mm (0.47") diameter steel tip to scary speeds. This uses my entire effective arm range! I see no way of making it even more powerful. It weighs about 4 kg (10 lb).
The rubber is prestretched from 27 cm to about 90 cm.
I call it the "Massacre Master" because that is what it can cause amongst Zombies - ten such monster bolts fired in under 10 seconds, easily. Short reloading time as you have both hands free. Easy aiming thanks to the long barrel.
I say with pride that I managed to improve Zhuge Liang's repeating crossbow, and the way I did it would have worked back then (albeit with a normal bow instead of rubber). Can you imagine what a few hundred of these could have done in an ancient battle?