What will it be like, then?
The most commonly discussed confrontations with a handgun (not happening in a shop or store) seem to have two forms: 1) a home invasion where the homeowner is responding to noises in the house (or an alarm) and is trying to find out what's going on, or 2) the gunowner is confronted or attacked on the street, in a parking lot, near a automated teller machine, or while going to the car.
In any of those cases, multiple magazines are comfort factors, but seldom used. I can't think of any account of a real-life civilian shooting (other than gang drug shootouts between gang members) where more than one magazine was used. In most cases its seldom more than 3-4 rounds used.
In any of the examples cited above, getting the gun ready (in the home or on the street) is going to take more time than you think. (In a home with kids, the guns likely to be secured in some way; on the street, the gun is probably being carried concealed, and you may be with a companion, and going into action may be difficult.)
In either of those cases, you aren't likely to have an opportunity for a well-aimed shot, and you probably aren't going to have much time to think about it... If you're lucky, you're going to point shoot and do it almost instinctively. The noise may be enough to make the perp think twice -- or it will open the floodgates.
In the home, you're going to be far better served with a shotgun (or carbine firing a handgun round -- maybe .40 or .45) -- a lot more firepower, and even then, it not likely to take out the neighborhood.
On the street you're going to be better served with a gun easily brought into play, perhaps while you're trying to elude the attacker.
If you're in any kind of densely populated area, you've got to be concerned about where the shots go after they're fired, and even if you're lucky enough to get one into the perp, you've got to be concerned that it doesn't got through the perp and into an adjoining house or two.
I simply don't see the advantage of a high-powered round with extreme penetration/pass-through capabilities. Or, for that matter, a magazine that is less than 10-16 rounds.
Hmmm. I have used guns before in self defense a number of times. The .22LR has been my cartridge of use in most cases and has given me a sense of respect and trust that few have in the round. Allot of important factors come in to play, but I think how well you remain calm and in control is probably the biggest. It IS true that when it happens, whatever training you have will instinctively kick in. Being able to handle a situation under stress is not easy and not likely if you have trouble with emotional self control. One of the most important things is to get a bullet in your target before they can harm you, whether it be a .22LR or a .50AE. Once you have hit home once, 9 times out of 10, you have bought yourself another shot and it keeps getting easier until the threat has been eliminated. Not only that, but at least for me, the "no going back" factor helps to lower the stress level.
I actually have allot of confidence in the 7.62x25 that I don't in many other rounds. Unfortunately, overpenetration is part of it, so unless you are using a round that is good about stopping in the target (heard good things about Wolf), I would not make it my round of choice. At present, anyone who takes to deadly violence against me on the streets will stop a 135gr 10mm bullet moving at over 1600fps, and I am fairly confident that in 95% of all cases, only 1 shot will be fired, per perp.