I'm sure many people have built pellet/slug catchers. I wanted to share a simple $15 (material cost) pellet/slug catcher that has proved very effective. It's built using a 20qt container, and one .8 cu. ft. of rubber mulch. Both can be purchased for under $8 each at Lowes hardware. When assembled, it weights approx.. 8-10 lbs., holds one full size target as the dimensions are: 16.2" x 12.1" x 8.6" (L x W x H) and can be shot from 10' away and the projectiles don't pass thru the container. Here are pictures of the supplies and finished product.