.17 to infinity and beyond.
Yes, you will need to get yourself a plastic straw. The straw will allow you to create a rigid path through the holes in the center of the baffles. Once the straw bottoms out against the end of the barrel, simply slide the looped end through the straw. You will leave the straw in and seated against the barrel until you pull the patch back through the barrel. The patch will then pull the straw out with it. Then repeat for each patch. Please note the straw needs to be longer than the distance from the end of the shroud to the barrel.