Modified Front Gas Cylinder (Elastic Edition!)

You have two ways to secure the elastic cord. My preferred method is to superglue the cord at the length you desire. You should glue a length of elastic cord longer than you need to the bolt first, then pass the bolt and elastic cord through the gas cylinder. At the end of the gas cylinder, superglue the cord somewhere within the cylinder such that it touches the top or bottom of it, avoiding the screw hole. Let the glue cure for a bit, then trim any remaining cord off. I promise it's a lot simpler than it sounds. 

Alternatively, you could tie a double-overhand knot around the end, but I found that doing this under tension is extremely difficult, so I fell back on superglue. It'll hold, at least for now. 

Print vertically.