Okay, guys, here is one shooting woman's answer to this perennially recurring question.
Donning my flame suit,
pax
* We can argue about this on another thread if you want to. IMO, a target gun is fired with the pad of the finger while a defense gun, esp a DA defense gun, is fired with the power crease. In any case, the measurement technique is the same.
** This is news?!?
- The best gun for someone who won't practice with it is -- none.
This is true even if the person is someone you love. It is true even if you really want her to carry a gun and even if she says she is willing to have it or to carry it. If she does not intend to practice with it, there is no point in getting her a gun. A gun is nothing but a dangerous nuisance to someone who cares so little about it that she will not take the time to learn to use it properly and well.
Yes, I'm heartless. But it's true anyway.
If this describes your woman, go do something else because the rest of this post isn't for you.
- There is no one best caliber for all women.
Oddly enough, women are all individuals. Asking what caliber is best for a woman is exactly the same thing as asking what caliber is best for a man. And the answer is, "It depends."
While it may be the most important thing about her in your eyes, her sex is simply not much of an issue when it comes to choosing a gun.
- Your woman's size (or lack of it) has absolutely nothing to do with which caliber will be best for her.
I've seen tiny little women with great big grins on their faces as they hammered away with full-powered "manly" guns. I've also seen sturdy-looking Amazon-woman types wincing from what I consider to be mild recoil. And vice versa, of course.
What I'm getting at here is that it doesn't matter if she weighs 90 pounds soaking wet or if she's taller than you are and twice as fluffy. Her hand size will matter when it is time to pick a platform, but the size of her body isn't going to tell you much that is useful about her tolerance for recoil or the caliber she'll prefer shooting.
- The caliber she'll prefer isn't the one you expect.
Some women love big calibers but hate small calibers. Some love 380s and hate everything else. Some hate .380s but love 9mms. And a lot of women find the recoil of a .40 too "spiky" for their tastes and think the .45 is more pleasant to shoot.
Women are individuals, just like men. You can't pick a caliber for her, or even predict which caliber she'll prefer, because you can't crawl inside her skin and feel what she feels when she pulls the trigger.
- There's more to choosing a gun than caliber!
Here we're really getting into it. Sorry if this bothers anyone's sacred cows, but a tiny little woman doesn't necessarily need, won't necessarily like, and possibly won't even be able to shoot a tiny little gun.
There's no point in getting her a .380 to avoid recoil, if the platform is a superlightweight gun which has lousy sights and a crappy trigger. A difficult little gun doesn't suddenly become easy to shoot simply because it eats a lesser caliber; sights, trigger pull, basic ergonomics, and weight will all have their effects.
You know this when you're picking out a gun for yourself. You may want to remember it when you're helping her pick out a gun, too.
- Beginners really should start with a .22 -- but that may not be best for her and her situation.
Another sacred cow here. All other things being equal, someone who starts out with a .22 is going to spend less time fighting the flinch, and will thus find it easier to learn to shoot well. The ammunition is cheap and plentiful, so you have fewer excuses to avoid the range, and we all know that more practice is better. It's not as loud as most other rounds, and so shooting a .22 is generally a more pleasant experience for newbies who aren't yet accustomed to the sound of gunfire. So it's great if she can learn on a .22.
However.
If she's only going to own one gun of her own, and needs a defense gun right away, a .22 is really a poor choice. The .22 is simply not suited well for defense. While lots of people have been killed with .22s over the years, the record shows that .22 is generally poor at stopping the attacker (which is the sine qua non for a defense gun). All things considered, it is notably easier to learn to shoot with a larger caliber than it is to improve the terminal ballistics of a .22.
Furthermore, if she's excited about a bigger gun, and annoyed by the thought of shooting a .22, it's probably not worth insisting on the .22. Let her learn on the gun she wants to learn on and even if it's a steeper learning curve she'll be more likely to hike up it.
- Size matters.
Hand size, that is. Since women generally have smaller hands than men generally do, and since most firearms are designed to fit the male hand, finding a firearm which fits her hand might be an issue. It is worthwhile to keep looking until she finds one that does fit.
To assess gun size, triple check that the gun is unloaded. Then check it again. Then, with the gun pointed in a safe direction which includes a backstop, have her put the crease (not the pad, the crease*) of her finger on the face of the trigger. With her finger's crease thus on the trigger and without pulling the trigger back, have her wrap her hand around the grip of the gun. If the grip can be firmly centered in the web of her hand -- not 'scootched' over to one side -- then the gun fits her well. Otherwise, the gun is too big. If the gun is very much too big, the recoil will be going straight into the joint at the base of her thumb when her finger is properly on the trigger. She may be able to shoot with a gun that oversized, but it will probably be painful to fire a lot of rounds. Even if it doesn't hurt, it can cause joint problems down the road and really isn't worth it in the long run.
- Looks matter.
Guys, your wives & girlfriends wear pretty underthings that no one else is going to see, even when they aren't in the mood.** Women wear stuff like that even though no one else will see it simply because we like to wear pretty things. If you want her to be happy tucking a gun underneath her clothes next to her pretty underthings, it's a good idea to help her look for a pretty gun and a pretty holster to carry it in.
- There is no such thing as a healthy adult woman who cannot retract the slide of a semi-automatic handgun.
If yours can't, it's because no one has ever shown her the correct technique. Get her to a class.
- She doesn't have to carry in her purse.
All other things being equal, on-body carry is a lot more secure than off-body carry. If she is willing to make minor wardrobe changes and is stubborn enough to keep trying until she finds the gear she needs, she can conceal a firearm underneath regular women's clothing and still look like the attractive woman she is.
- Finding a holster is a different ballgame for her than it is for you.
Newsflash: her body is shaped differently than yours. Your cast-off old holster probably won't work well for her. But there are holstermakers who specialize in women's gear, and it is worthwhile to seek them out.
- You are probably not the right person to teach her how to shoot the gun you just bought her.
Yes, really. If you want a list of reasons why, PM me. This is getting too long and I've already offended enough people for one day ...
Donning my flame suit,
pax
* We can argue about this on another thread if you want to. IMO, a target gun is fired with the pad of the finger while a defense gun, esp a DA defense gun, is fired with the power crease. In any case, the measurement technique is the same.
** This is news?!?
Since my wife is home a lot more than I, we got the gun she wanted. I told her why I thought a 9mm would probably be the best compromise of all the factors. She agreed. We went to a couple of gun stores and they all wanted to push the "ladies" favorites on her. 
Finally I showed her the Taurus version of the Baretta 9mm we shoot in the Navy. She loved it and that is what we bought. I shoot it just a little better than she does, but I qualify expert marksman in the Navy. 
I wouldn't do a thing but hand it to my wife. She asked him to take the trigger lock off so she could feel the trigger pull. Again, the gun comes back to me. :banghead: and I handed it right back to her. Anyway, she picked out what she wanted based on feel in the hand and feel of the trigger pull. (It was a nice SS Ruger P345). I haven't been able to hit crap with that gun 
