1. If a person believes that there is a "One Stop Shot" based on calibers, then they need to take some physics classes. The ONLY way there is a "One Stop Shot" is if you hit the CNA, which included the brain, or hit them in the spinal/cord. And this can be done with everything from a 22LR to a 500s&w. The only difference is that a larger diameter bullet has a slightly better chance of hitting a target, and a heavier bullet will generally penetrate further and again have a better chance of hitting a target. Target meaning the CNA Spine/cord.
2. Over penetration is a bogus concern. Both New York City and Los Angeles police departments have done shots fired studies of their officers, and found that on average, only about 27% of shots fired by police even hit their target. Now, assuming you, the common civilian under such stress will shoot similar to a trained police officer, you have a 3-1 better chance of totally MISSING your target than you do of worrying about over penetration. Missing the shot is the ultimate in over penetration. The next target is getting the bullet at full velocity.
3. Assuming you are a better shot that the local police, that you know how to maintain composure, and that you don't miss; then you should know exactly who/what your target is. If you are shooting at someone in a crowd, and/or with people behind them, then you deserve to go to jail. Just because you have a gun, doesn't make you the world's savior, nor does it mean you're suppose to shoot someone with it. Even police know when NOT to shoot. And assuming it's an infiltrator into your home, or a self defense act in an ally or on the street, there won't be innocent bystanders behind the criminal. And at that distance, you shouldn't be missing. (If you are, you need to get rid of the gun until you've practiced and become more proficient).
4. And even if you were foolish enough to shoot at someone who had a crowd of people behind them and the bullet was to over penetrate, it is so unlikely that there will be enough velocity and energy left to incur any real fatal injuries to the person beyond the criminal. Unless of course they were standing directly behind the bad guy at around 6 inches.
In the day of many 357 magnums, they used a lot of flat nose type bullets like wadcutters and semi's. Very easy to over penetrate these rounds. Same with most any solid or FMJ type bullet. The #1 main purpose of a hollow point bullet is to slow it down, reduce penetration, and eliminate the prospect of over penetration. Expanding into a larger diameter and creating more damage is just a side additional benefit. But in order to ensure that a bullet would expand as designed, you had to increased the velocity of the bullet. The easiest way to do this, is to load the ammo with the exact same amount of powder, and simply reduce the weight of the bullet. That will automatically increase the velocity. So a 125 grain hollow point is definitely better than the 158 LRN, WC, SWC, etc... Assuming you are foolish to shoot when there's a crowd of innocents standing behind your target. However, with today's ammo, and the 158 grain bullet also made in hollow points, you are just as safe shooting the 158 grain hp as you are a 125 grain. And if you think the 158 grain still has an over penetration issue, then you really do need to go back and take some physics courses.
Oh FWIW: The Federal Hydra-Shok, which is considered a very respectable Self Defense handgun bullet, is WAS ONLY PRODUCED in the 158 grain HSJHP for the very longest time. It traveled at 1240 fps and 535 ft/lbs. Recently, they cam out with the 130 grain. But they did so specifically for a "Lighter" shooting bullet. Not because of penetration. Normally, the 130 would be a lot faster than a 158 grain. But the 130 grain only goes at 1300 fps. But it's also less kick and less flash for personal defense for those who need it like that. But the 158 grain HSJHP is their MAIN hydra-shok 357 magnum round. There's a reason for this.
