This one is pragmatic. And moreover it seems to be easy to convert it into a "take away" catch box (which could be very useful for those who need to go somwhere else than own backyard to shoot for a longer distance than couple meters). 3 more alumium tubes for the hanging towels joined together with some stiff wire for the upper part of this invention, and it's ready to go. Just wrap it, attach to your backpack and walk/run/ride/drive straight to the forest. Good idea, maybe I will use it (it's much bigger - especially in width - than ikea hanging storage*).
*I've made a catch box from ikea hanging storage. Just cut off middle shelfs, hang 3 old t-shirts inside of it and it's done. You can fold it, attach to your backpack (it's very light) and while traveling on - let's say - a footpath you just unfold it, hang it on a tree and shoot. Simple as that. But because it's narrow it wont work well for a longer distances (like 50 m) - a lot of ammo will not land in it. Your idea delivers better "catching ratio" for longer distances and it comes with small price of a bit higher weight to carry. Congrats. And it also looks natty.