Shot Trap --- what to use/where to find it

I've got my base built. What's everyone using for their first layers of material to shoot through before their final stop? Where did you purchase your material?

I use 2 layers of carpet on mine. Backstop is some kind of galvanized material about the thickness of 10 sheets on tin

I bought rubber mats from Lowe's.... 3 layers will let most get through for metal to stop it.

Thanks fellas.

I got a buddy that is supposed to give me some carpet. I looked at the rubber mats at Lowes but couldn't determine what I needed.

I think y'all got me pointed in the right direction.

Where is everyone getting their steel backstop?

I'm using sheets of tin put together for my backstop. Not sure how many sheets I'm gonna use yet.

I've seen pics of someone who used a metal street sign.

Got my rubber backed carpet from a guy who worked at cintas and the metal come off an old ice maker.

I got mine from a metal fab shop. They had tons of scrap pieces that were in a stack. The guy drug it out of the pile and cut it to the size I needed and charged me $15. A buddy of mine got his from an HVAC business for $10. We use 14 gauge and have yet to have it penetrated.