OK, I got it filled up. First, I filled it with kittens, but that only worked until the smell was unbearable. Then, I emptied it out, lined the perimeter of the bag with carpet, put 30 lbs of sand into heavy duty trash bags, and dropped that into the bottom, filled the rest with old clothes, and packed them in as much as I could. It feels just like the ones at the gym.
Favorite Fighters (random order):