Howdy!
Moved to TN a few months ago - but still love me some NFOA.
Anyhoo - I am experimenting a bit with some DIY bullet traps.
Live out in the boonies and neighbor has like 100 acres or so - and a range setup.
Being the cheap bastard that I am - thought I'd play with a DIY bullet trap idea that's been floating around a bit.
A container with rubber mulch inside as the bullet stop.
I attemtped an 18 gallon (16x16x24 ish?) tote and 3 bags of 0.8cu foot rubber mulch nuggets.
From 20' away, the first round from 40s&w loaded nominally - was stopped. By the fifth round, the back had blown out and there were signs of impact as well.
16" of rubber mulch doesn't appear to be enough by itself. Which runs counter to online posts suggest.
24" and maybe some sheet metal near the "back" would probably do just fine. In a wood box would go nicely as well.
Butttt rubber mulch is about $9 a bag. A traditional angled steel plate to ricochet into sand is a much more tried and true approach - and probably comparable / cheaper in cost.
As an indoor load test (IE: garage) it's interesting. Note that it's not a proper back stop - and firearm discharge laws still apply
Lastly - I tried some of the sense foam interlocking sheets (four 24x24" things for like 17-20$) as a face to the mulch. I thought it might self heal a little. NOPE.