I fixed my rubber cover on my vortex venom to do exactly what you are wanting. I took some elastic drawstring, about like what you find in the waist of a jacket to cinch it around your waist, and poked a tiny hole in the top right behind where the glass is with a knife. Take your elastic drawstring and tie a knot on one end, thread the untied end through the hole from the bottom side( inside of the plastic cover). I then run it down the side of the receiver and underneath the receiver and tie a small loop and loop it over the bolt head that tightens the base down to the rail. It works PERFECTLY! I through my gun across my back the other day and looked up after going through some thick stuff snd the cover was dangling by the elastic string. I'll take a picture tonight.