ORIGINAL: Bowtech 360
Just put a ratchet strap around the straw and put it as tight as it wil go. I think this should stop your arrows if its tight enough.
X2. When I was still shooting into straw, I had three bales stacked, and a ratchet strap around them to keep them snug. My setup was also under roof to minimize the bale deterioation and keep the strap from dry rotting. The nice thing is over time to can resnug the bales by just making a click or two with the ratchet, and you're good to go. Just try not to shoot the strap
