Personal defense ammunition is a very important subject. There are many factors to consider when choosing a personal defense round. For example you live in a tightly knit neighborhood, you could miss a shot, and send a round into an innocent house. The results could be terrible. Others say penetration is the key, and you must have penetration to strike a vital organ, which is also true. When choosing a defensive ammo you must weigh your ability with your common sense.
I feel hollow points are much safer indoors and safer also to everyone else around. Of course the best defense would be a 12 gauge shotgun, but that not available hollow points are the best bet. Frangible ammo has good knock down power, yet it fails to penetrate deep enough to damage a vital organ or tissue. High velocity light weight bullets do not penetrate as well as heavy slow ones. It is a know fact. A decent hollow point will travel thru a layer of drywall or glass, expand and also penetrate deep enough to cause substantial damage. 12 Inches is the minimum required by FBI. This is very effective for knocking down and stopping an attacker without the worry of over penetration. So wouldn't more penetration be better? While a 158 grain lead semi wad cutter may penetrate 18 inches thru four layers of denim and absolutely incapacitate a bad guy, I could miss and send a stray round into my daughters room. For me the less chance I have of hitting an innocent person while still stopping an attack is a win, and that I can live with.
The best defense bullet is one that penetrates at least 12 inches while expanding as much as possible. Velocity has something to do with it, as we want to obtain the 12 inch mark however, a slower heavy bullet will penetrate just as much as a lighter +p round. A heavy bullet retains more velocity after impact allowing it to penetrate better. It also makes less muzzle flash and less recoil making it easier for follow up shots. Lightweight +P rounds are typically not necessary unless you are using a snub nose or the BBL is less than 3.5".
Regardless of what personal defense ammo you choose, be smart. In my opinion (for what it is worth) hollow points are the best ammunition for home or personal defense. The idea is to stop the attacker, which is exactly what hollow points are designed to do. They transfer energy extremely well into the target, as well penetrate the necessary 12 inches needed to hit a vital organ. Keep in mind, placement is key. No matter what size the bullet, you need to be able to place the shot, and well. So practice, practice. While revolvers digest just about anything with powder in it, (which is why I prefer a revolver over ACP for home defense) semi-autos are a bit more finicky. The experienced shooter says, "Run at least 150-200 rounds of your selected defensive ammo thru your firearm. If it goes off without a hitch, only then can you call it your defensive load." Advice that should not be ignored. Every ACP has a different ammo it absolutely loves to feed, so try a few brands and choose the one that feeds the most reliably for you. Also, try to find ammo that has a low muzzle flash. In a dark room, a large muzzle flash will temporarily blind you, making it impossible for follow up shots.
For what it's worth, this is not to say I am right or wrong or even worth listening to. What it is saying is that I have weighed my education and common sense with my own ability. When lives are on the line, there is no room for pride and no time to wait for the perfect shot. Educating yourself is part of the responsibility of owning a firearm, and that is common sense.
Personal Defense Ammo
12 Gauge Shotgun - If you have in your possession a 12 gauge shotgun, congratulations. You have the most effective personal defense weapon available. Load it with a 0 or 00 gauge buckshot and Dirty Harry himself would be an idiot to not set down his weapon and lay on the ground. No who, what, where, this is the best in personal defense weapon period. One blast from a 12 gauge buck shot and an attacker will be no longer be a threat or an organ donor.
Hollow Points - Hollow points are bullets that have a hollow tip and expand upon entry. This expansion causes resistance forcing the bullet to transfer its entire energy into target without over penetration. Hollow points do not penetrate as deep as other rounds because their function is to displace their entire energy into the target incapacitating and stopping an attacker. These rounds are very effective and will (if placed right) get the job done with less chance of sending a stray into the neighbors house. (Again placement is key and a missed shot can still be deadly.)
Frangible Ammo - The claim is frangible ammo is designed to explode or fragment upon impact. This explosion transfers all the energy of the bullet into the attacker thus stopping and incapacitating the attack. This ammo is supposed to disintegrate upon contact with a hard surface such as drywall or glass, making an innocent person in another room safe from a missed shot. These are merely manufactures claims and have been disproved time and time again. These rounds use ultra light weight bullets that fly extremely fast. The numbers look impressive, and fool many people. We know better. The heavier the bullet the greater the momentum and the deeper the penetration. We do not recommend using any hyped up Glasser, Extreme Shock, or other frangible ammo for personal defense. If the ammo really as effective as claimed, Remington, Winchester, Federal and Speer would have a similar round on the market. Do not believe the claims, they market huge price tag and huge hype to new or uneducated shooters who are just learning about protecting their homes and family. I would never trust any of these in any of my firearms. What are these good for? They are great for blowing up mellons and waterjugs. Nothing else.
Recomended Personal Defense Loads by Caliber.
These loads are in no particular order. All of these loads are considered to be top quality and personally tested by Dr. Gary Roberts for Personal Defense.
9mm
Barnes XPB 115gr HP (35515) loaded by Cor-Bon (DPX09115)