If you want to catch fired cast bullets without any deformation to study obturation, bore ride, and other features of bullet performance in flight what is the best medium? Many years ago Dr. Franklin Mann, in his book "The Bullet's Flight from Powder to Target" found large boxes of oiled sawdust to be the best at capturing undeformed bullets. I have also accidentally found bullets in the spring after a deep winter snow buildup that were captured and gradually decellerated and deposited unharmed on the grass to be found after snow melt.
What methods have been devised since Dr Mann's work that are repeatable and easily duplicated in the home ballistics laboratory?
Again, I DON'T want to test expansion. I can do that with well-soaked newspapers. I want to catch the bullet as it is after firing but unaffected by impact.