I have been filling synthetic burlap bags with old clothes & towels & it stops them well, none have gone thru yet. Bout the only downfall is the arrows hang down in the target instead of sticking straight out making shooting groups rather destructive. After cutting 3 arrows I painted 6 2" bulls on it, laid it on its side & I shoot the top 3 & retrieve my arrows. After a bit I flip it over & shoot the other 3. I was using 4" styrofoam const insulation stacked 3 thick & it worked well also. My fixed blade heads came out of this pretty easy but the field points can be tough. The styrofoam makes a bit of a mess & wear out rather quick from broadheads thats why I switched to the bags, that & I got a bunch of them free.

For field points with the bags I stuffed them with old poly tarps cut into pieces. The arrows stick out much straighter than the rags so I can shoot groups but the broadheads zip right thru.