Anybody have any experience with these?

http://www.letargets.com/html/blocks.html

I'm thinking about setting up a range in my backyard with a stack of these. I'm thinking of
building a wall either 4' x 4', or 6' x 5'. These things should be able to handle anything I can
shoot at them. I can get about 55 yards from my back door, or 120 yards from the front of
my property.

Anybody else have something similar? I saw Jim Scouten talking about an indoor range thingy
made from recycled tires, but I haven't been able to find out anything about it...

Thanks

Sam

They look good but why not get some free used tires from your local dealership or your local jiffy lube?