Also of note, Hornady offers a Foster slug. It is alleged to be "lead alloy". A phone-call to Hornady further corroborated the implication that it is less ductile than other Foster slugs on the market, Federal DP not included. Hornady's website offers a photograph of the expanded slug, as does the civilian packaging (in the American Whitetail line). It shows a slug with a "dish" in the middle, collapsed to about 1/2 it's unfired height, and bulged out radially, but truly maintaining impressive integrity. Hornady informed me via the phone that this was a photo of a slug fired into ballistics gel, likely no further than 10 feet from the muzzle. If this is indeed the case (and I purchased some to test, scratching/slicing one with a knife, it is indeed a harder material than the Remington Slugger), it offers a cheap and unique alternative to the Federal DP if you're shooting deer-sized or Black Bear game, and want some expansion without giving up too much penetration/weight retention.