homemade ballistic media???

[Jack]

You can usually recover bullets in water jugs. You have to line up a bunch of them, but empty milk jugs are free....
And, since it's water, you don't leave crud all over the range, once you pick up the jugs.
Bundled newspaper is another alternative.
Niether one is a true comparison to how a bullet performs in game animals, but for comparison purposes, it can be interesting.
BTW, you know those perfectly mushroomed bullets you see in the ads, and pictured in loading manuals? A lot of those are created by shooting them into swimming pools.