Very useful, save for regarding .410 pistol rounds: This person makes a silly error in his presumption. Presuming (plausibly or not) that .410 is "half" as effective as 12-gauge (five pellets versus nine pellets), he drops the effectiveness not by half of overall effectiveness, but rather by half of the difference between shotgun and regular handgun effectiveness (8:30 point in video). Thus, by his stated standard, he ignorantly inflates the effectiveness of the .410.
The reality is that his "half" estimate is not in accord with the laws of physics attendant to such ballistics studies. Rather, it is a Teabrain-type single-thought presumption, perhaps driven by a preference or bias. Being a fan of .410 handguns, I myself have to guard against such errors of bias. Thus, I will be mild in my criticism of him. But, my duty of righteousness requires me to point out his error.
The truth is, modern .410 specifically-for-handgun defensive rounds are more effective than his Teabrain estimate might suggest. Too many other factors enter into the matter. More importantly, though, the .410 handgun's benefit comes not from increased stopping power with a full impact, but rather from increased hit probability from multiple projectiles, and the psychological as well as physical impact on the bad guy. Thus, I have called for loading such revolvers with the first round as .410--fired when the defender is still acquiring situational awareness and the target--followed up by regular .45 rounds, after the bad guy has been put back at least slightly, and the defender has gained cognizance of the situation. That's not to say it's "bad" for defense functions, as some would argue. But rather, it simply is NOT AS GOOD as the YouTuber here asserts from his Teabrained analysis.
There are other benefits of the .410 handgun--compatibility with long gun, reduced ballistics traces, versatility in use, legal/political factors, even heritage matters, etc. But these are beyond the scope of this video. See TDF 28 for more.
Above analysis adapted from my comment HERE.
TDF INDEX: Cats, Guns, and National Security: THE DAILY FUDD index. https://catsgunsandnationalsecurity.blogspot.com/2021/03/the-daily-fudd-index.html
