The question is asked often, answered often and often answered wrong: "What's the best gun?" There are several important criteria for selecting a gun that will be used for defensive purposes. My list looks like this:
Of those criteria, there is one that is absolutely inflexible: reliability. I want to talk about just that one in this column.
There is more to reliability than some folks realize. A gun is not just a tool, but a working mechanical system. People who don't understand that often have problems that could easily be avoided. For example, reliability in a modern semi-automatic pistol is not just dependent on the build quality of the basic firearm. It is also dependent on its maintenance, magazines, ammunition and its operator. Any machine, including a firearm, must be well made if it is to be reliable and continue to be so throughout its useful life. Actually, that's the easy part. Today's competitive firearms market has pretty well shaken out the junk, as least in the realm of serious defensive handguns. But a well-made gun is only the beginning. A relative of mine has a small, easily concealable Beretta pistol that he has carried for years. It wasn't until recently, however, that he actually tried to shoot it for more than the odd round while walking in the woods. He found out that, although it is certainly well made, it is certainly not reliable for self defense use. It is designed to function with full metal jacketed ammunition. Not a good choice for self-defense. It jams nearly every round with any decent quality hollow-point ammo. And the ball ammo even jams frequently with certain of his magazines. To top it all off, it is .32 ACP caliber. He now carries a Glock 30.
So, let's look at magazines. Often, students arrive at classes with a decent quality gun that they have not really put through its paces. They find out about reliability very quickly. The bargain price magazines that they bought (because the class required more magazines than they already owned) will cause problems pretty quickly. The magazines are an integral part of the system that is the functioning firearm. When they don't work, the gun doesn't work. Sometimes the students are ready to give up on the gun, when the only problem is one (or more) magazines. Once they change to decent magazines, they are back in business. Sometimes the magazines start out okay, but become damaged. Again, fix or replace the mags and you've fixed the gun. You need to test every magazine you have for a particular gun. And, you need to keep them clean. If you find any that are problems, fix them, replace them or throw them away. Just understand how they relate to the functioning of the whole system and you'll be able to sort it out. This, by the way, is one place that revolvers really have it over the auto-loaders.
The other most common problem is ammunition. Not all guns work well with all ammo, even quality ammo. Some guns run great on range ammo, which for most of us means full metal jacketed (FMJ or "ball") bullets. But hollow points, which are best for defensive purposes, can be another story. We tell our students that they should be able to run 200 rounds of their self-defense ammunition through their carry gun without a single malfunction. If it doesn't meet that test, don't trust it. Some ammunition and some guns just don't get along. That doesn't mean that either are inferior; they just are not the right combination. If you find that, be prepared to make the necessary changes. Sometimes the gun just needs a break-in period. Sometimes a little gunsmithing will solve the problem. In any case, there are enough choices in premium defensive ammunition that finding one that works with your gun should not be a problem. A good example became evident fairly recently, with the introduction of very lightweight revolvers. The substantial, if not downright brutal, recoil of the ultra-light revolvers is causing some types of bullets to work forward out of the casing crimp, at least enough to bind the cylinder rotation. This is usually associated with un-jacketed bullets and the newer guns have a "jacketed +p ammo only" warning. However, I've seen it happen even with some brands of jacketed ammunition. That's why I say, revolver or auto, primary or backup, test your gun with your carry loads. You need to KNOW that they will work together.
The operator can also affect reliability in several ways. Auto pistols can jam from the notorious "limp-wristing" problem. Actually, this is often "limp arming." Whatever, it causes operator induced problems, and it isn't the fault of the gun. The solution is a strong stance and a high, firm grip. Just as the gun is a system, proper stance and grip on the gun are also parts of the operator interface system. Also, the way the hands grip the gun can cause reliability problems. I've seen finger and thumb placements that have put pressure on the auto pistol slide release, causing the slide to lock open after every shot. I've seen grips that put pressure on mag releases and cause the magazines to drop out, or not drop out when you're trying to reload. Or grips that inadvertently activate manual safeties, or don't deactivate grip safeties. I even know of a few folks who accidentally hit the cylinder release on revolvers. Often, a gun can simply be too big or, yes, even too small for someone's hands. Any of these things are genuine problems that affect the reliability of a gun at the moment that you urgently need it to function. The solution is to alter the interface or change to a gun that doesn't contribute to the problem.
What I'm saying here is that reliability is not just a single dimension, addressed by simply using a good quality firearm. All guns are not the same for all people. And the solutions are not the same for all people. This can become obvious in police service pistols where "the same gun for everybody" is the norm. There are vast differences in individual users and considerable variation in training programs. Combine this with both firearms and ammunition purchased through "lowest bid" contracts and all sorts of problems can arise. Remember, reliability, most of all, means that when you need it, you have confidence that your gun will work. If you have addressed the possible problems in advance, then your confidence is well placed. If you have not, there can be a terrible price to pay.
As you can see, if someone asks me what gun they should buy or use, they don't get a one-size-fits-all answer. No matter how much I may like or dislike a particular firearm, you may find just the opposite. That's fine with me. My job, as an instructor, is to help you find the right gun for you. There is only one "best" gun, and that's the one that works for you when you need it.