Back in the early '90s, Georgia changed their hunting regulations for handguns. Previously, they had run with "any centerfire, .25 or larger, with a barrel longer than 4 inches" (or something along those lines; it's been nearly fifteen years, so cut me some slack.)
Some bright spark realized that this would allow you to use, say, a target version of a Beretta Jetfire to shoot at Bambi, and so the regulations were revised to eliminate references to caliber and barrel length and instead set a power threshold: To hunt deer, a handgun needed to generate 500 ft/lbs of energy at 100 yards. All of a sudden, people who had been harvesting deer with scoped 8 3/8" Model 686 Smiths were out in the cold, as no factory .357 Magnum ammo loaded back then put up those kind of numbers.
In answer, Georgia Arms started loading their "Deerstopper", a 158gr Speer Gold Dot bullet propelled to a downright zippy 1400+ fps out of a 6" revolver barrel. They printed the ballistics right on the bag so that you could show them to any inquisitive game wardens, too.
In the intervening years, Georgia revised their handgun hunting regs yet again, and Georgia Arms has kept the "Deerstopper" name while throttling back the velocity.
I found some of the original ones in a box of miscellaneous .357 Magnum ammo that I took to the range on Sunday...
Let me tell you, when you cap off a cylinder full of those things out of a Performance Center 627 V-Comp with a 3" barrel, you don't stand around wondering if the gun went off or not. Neither does anybody else on the range.