Upon reading a few posts on the web of people building these. The main reccomendations were to keep the tires tight(no sound leaks) and to place rubber or plywood covers on each end with smaller holes to shoot through. Some even placed rubber/plywood/carpet every other tire to create more baffling. Many also mentioned lining the tires with insulation.
It will be a while before I build the range, so plenty of time to think it out.
forpest,
That does sound nice. I went to a really awesome home range a while back. The guy had a ~15x30 cooled reloading/gun room on the back of a large shop. He had a covered porch across the back with concrete slab and two ranges. One range was ~100yds with about 50 pistol and rimfire gongs, the other was set up to 400yds with rifle gongs. He had a concrete bench for the rifle range. It was the nicest I've ever seen and really got the wheels turning.
