Have thought about this question for some time. The effectiveness of a handgun shotshell in self defence. I have done a little pattern testing of 38 spec out of a 4" revolver. But I see where shotshells can be bought for other calibers as well. Has anyone seen any data on geletin tests or penetration tests, etc? My guess is that they might be effective maybe 6 to 8 feet. That range would be enough to keep a carjacker out of your car ok. Just wondering.