Pretty easy build with what my old man had out in his material shop(Contractor). Used 2" blue foam that I cut out with a jig saw after tracing the concrete tube on the sheet. I think it's 6 pieces of 2" foam. Foam really wasn't moving anywhere after my perfect force them to fit cuts but I taped the back anyways. Free hand kill zone may be a bit off but whatever, it helps visualize. Arrows are stuck pretty good but slide out smooth once you get em going. Was doing pretty good but put one low and broke the tip and the pine pitch broke free. Was amazed it didn't just blow up!
I should mention that the arrows don't get too far in. 2-3 sheets probably would've worked.