Shot placement is much more important than what caliber you use.
Here is a ruger 10/22 (22lr for anyone that doesn't already know) killing many people quickly in a short period of time. It's graphic, but it really doesn't matter what caliber you think is best, because they all do kill. This psychos rifle had no problem taking down everyone VERY quickly and effectively. Some of the comments I read about calibers are so silly, they're embarrassingly cringeworthy. The certain folks that abide by youtube ballistic gelatin test videos, the FBI's protocol, and what their buddies tell them at the range is the best shine often. Don't be "that guy" PLEASE, for the sake of the non believers sanity.
Um, ok so he was able to "take down" "quickly and effectively" 3 senior citizen women, a 52 year old man, and a teenage girl with 22LR. Based on that I'm not going to decide to use it as a defensive caliber unless I have no choice. You can effectively kill a person with a pencil to the jugular, but it'd be better to use something else.