These are photos of a pellet trap I constructed that crushes together a stack of magazines. The front partition moves by turning the wing nuts that extend out the back of the box. The connections are Allthread ¼ inch. The front has a bar across it that was originally the wall section of a shelf support. Use binder clips or magnets to hold the targets. Use a lot of screws to hold the back on, I used 10. There is an allthread compression rod on all 4 corners. The magazines were compressed until I could not turn the wing nuts any longer.
Now the useful part. This target holder and pellet trap will stop a pellet- any style or weight - from an FX DreamLite Compact .25 caliber on full power from three feet away. I also tested a Marauder .22 on full power from three feet. No penetration. The front of the compression area is ¾ plywood— well, what we still call ¾ plywood. Actually it is not ¾ thick. Both the .22 and .25 blew through the plywood like it was tissue paper, but the compressed magazines stopped the pellets. Nothing went out the back (also ¾ plywood).
Built from plywood leftovers, but one quarter of a 4x8 sheet should be enough to build it. The box can hold an 8.5x11 target hung from the front bar. I think a larger one could be built using compressed newspapers.
AD2