Well, we all know what they say about opinions. I carry a 9mm a lot, but NOT because it’s “The best” defensive round. Rather, it works in small ight guns that are easy to carry. For sheer effectiveness on a live target, a bigger, heavier round will inevitable result in a quicker “stop” (despite all the “cartridge doesn’t matter” gurus-all who quickly follow up with “carries more rounds”). ALL rounds are lethal, but to defend oneself lethality plays a distant second place to a rounds ability to bring an attack to and end Right Now. If a thug committing an assault dies from being shot the day AFTER he has proceeded to do You and yours in then it really doesn’t matter to YOU. I’ve been shooting/hunting for 68 years and have seen the effects of different calibers on a lot of critters. If you ever face a dangerous animal you’ll not be wanting a small or medium caliber like a 9 or the new whiz kid 5.7. Frankly the “best” defensive gun/round would a 329 Smith PD if one could handle the recoil well enough to shoot it quickly.. All firearms are compromises, but for sheer effectiveness in a controllable easy to carry package an old fashioned .45 1911 is darn tough to beat. A person should carry whatever works for Them (first rule-have a gun) but do not allow yourself to be fooled into thinking that small bores are “equal” or that capacity can make up for a lack of shooting skill-they aren’t and it can’t. A solid hit from the first or second round trumps a hit with the 10th every single time.