Ahh...Watson stole my thunder. No screws on my barrel though. I had bamawife sew a fold on either end of the elastic and passed a length of paracord through each loop. The rear loop ties around the forward scope ring. The muzzle loop is just big enough to force over the muzzle and secure about an inch back from same. When not in use I detach at the muzzle and wrap it around the scope tube.
A buddy suggested velcro dots along the length of the barrel, and same on the elastic, but I have not been able to make those stick on the barrel.
I figured the length out so that slightly streatched, the strip stays taunt and away from the length of the barrel. On or off doesn't seem to effect accuracy, but again, I am not a shining star in F-T/R.