So, I've been working on welding together a pretty mean slingshot crossbow but decided to small scale it first to ferret out any unforeseen issues with the pulleys or the frame. What I wound up with is this, a smaller draw length extended slingshot. It's 3/4" hot rolled square tubing, welded up. The pulleys are actually climbing emergency sheaves for carabiners, made by petzl. My concern was the amount of play in the pulleys themselves. The pulleys have a 5/8" bore, but I wasn't really comfortable drilling a 5/8" hole in 3/4" tubing for the full size crossbow, so I drilled this one for 1/2" grade 5 bolts. The play in the system there definitely seems to increase the friction somewhat, but I'm satisfied from the small scale it'll work we'll enough for the final project. Overall length is about 48 cm with the handle about 30 cm from the front end for an overall extension of roughly 80 cm. It's currently racked up with theta tube red, though I have 25' rolls of all colours, so I might swap it out for blue this weekend.