If you have been following the Terminal Tuesday test results, you know hard-cast bullets will not expand inside 10-percent ordnance gelatin. They do, however, penetrate incredibly deep and usually do so in a perfectly straight line.
Some argue that non-expanding bullets are not the optimum choice for self-defense, because they do not create as large a wound cavity as their expanding cousins. As with every other aspect of terminal performance, this assertion is debatable. Ironically, some who suggest they are not ideal for defense against bad guys will readily suggest them for use against a marauding grizzly.
Regardless, if penetration is what you want, a hard-cast bullet is hard to beat, and Buffalo Bore is the premier source for hard-cast defensive handgun ammunition.