If I were to make a berm to shoot at, about how tall should it be? I've been to the range in Dumont, and those seem like they are about 8-9 ft tall. I think that would be just fine for most shooters, then just keep an eye on the new shooters.

I was thinking about just using some old tires filled with dirt like a rammed earth home. Anyone have an idea of anything that'd be even easier/cheaper?