Home Depot box, steel sheet(8" x 14" x 18 gauge), old towels, denim pant legs, sand bags, adhesive & Gorilla tape.
Have used this in my RV & outside for 2 years with a moderated 2240 pistol and this box trap is very quiet.
You get the idea. Keep folded sandbags loose and the cross-weave absorbs most of the energy.
I'm using Crosman 14.3 domed HP pellets & they just drop to the bottom of box.
I like it! Good way to collect the spent pellets - mine seem to find every crevice and crack and escape from my backstop. :)
Best pellet trap I've made so far is a cardboard box filled with rubber landscape mulch from Home Depot or Lowes. I'm about ready to clean it out. I've read where you can dump the pellets/mulch out of the box and into bucket of water. Pellets sink and the rubber floats. I'm going to try that using my wheel barrel to clean it out later this summer.
Looks good! My first trap was composed of rags and towels. I cast my own firearm bullets so I have been saving pellets for softening my alloy, One problem with towels not seen in denim or plain rags is pellets get tangled in the terry material and are sorta difficult to pull out, newbe mistake. I went with duct seal in a shoe box and it's working well...