( For some reason the paint program malfuntioned during this drawing so it looks very bland without any shading.:( )You have the frame bent and are ready to pad it. You also need to secure the tubing to the frame and ammo pouch. What items do you want to use? On another note, an experiment was conducted today to see nails can be driven through steel water pipe. The answer is no, you cannot drive a nail through water pipe. Not only does the nail bend (several were tried) but it stings your fingers. Thin electrical conduit was another story. After 5 hits there was a nice hole in the pipe. Too bad the pipe in the basement is water pipe and you only have 2 matches or the shotgun might have worked.
You could've gone back to the fire and heated the pipe before punching. A T-shirt, rolled tightly and wrapped with cord or wire will serve an an slow burning match, think indian fire pouch. I like loud noises, so I would go out of my way to make something that went boom.
As for the sling part, I used to have a wrist rocket, and I swear it had two things of surgical tubing going through the leather straps, but I can see how that would work on this, so you can slide the tubing through the two slits on the leather holder and over the ends of the frame til its tanut in the middle.
Tobes is on the money! Using two pieces of a tee shirt, you wrap one around the grip and one around the forearm rest. Then using the electrical tape ( the string might not be as comfortable ),you wrap each piece firmly to the frame. Then you push one end of each piece of surgical tube ( remember you found two ) over the rod ends as far as you can. You then take the ammo pouch and thread each tube through a slot. Once you determine the proper lenght of the tubes you fold the tube in half right at the slot in the leather. Now you wrap the string around both sides of the fold so it stays folded and trim the excess tubing off. The only thing remaining to do is wrap more string around the tubeing where it goes over the frame. Congratulations! You are now armed! PWFNP