I just got a 9mm which is a caliber I've not had any experience with. Actually I got it for someone else, but might buy them a different one and trade them. It is a Taurus 709 slim which is sort of targeted at the concealed carry crowd. I'm mostly familiar with my 357 mag. The 9mm is quite manageable by comparison. Even with the relatively small automatic I feel that I could put a number of bullets into someone breaking through a door in under a second.
For home defense purposes I would suggest a more full sized automatic mostly because it holds more rounds. Might be even easier to rack and fire also. Not sure since I've not played around with one. The one I got was sort of a spur-of-the-moment purchase for a family member since there have been troubles with tweekers in my area of late.
In contemplating tactics recently and watching some of the home invasion footage on youtube, I would suggest that the most important thing a person can do is to have a well thought out and well rehearsed plan about where in the house to retreat to. and how to mount an attack or defense from there. Practice it a bunch so it is Pavlovian should one's window breaking be what wakes a person up.
I would also suggest to analyze various available footage paying attention to the behavior of the home invaders and put yourself into their minds remembering that in the common case they will be learning the layout of the house as they go. It is interesting to note how common it is for home invaders to work in groups of three.
Not sure if it's been posted on this board or not, but here is a rather delightful bit of footage:
https://www.youtube.com/watch?v=stOcTAADa38Shows how useless 911 can be and it is awfully amusing when the woman loses patience and hangs up on 911 to call her husband in order to get some actual help. Apparently Asian restaurant owners are specifically targeted because they close late and often take the night's earnings home. Interestingly and not surprisingly the strong consensus is that this woman should be granted instant U.S. citizenship if she wants it.
I was going to write a long post but I'll keep it short and sweet (also, everything here is just
my opinion, not
the only opinion). I've done a lot of research on calibers and firearms over the past oh... too many years. I own one pistol caliber: 9mm. I own several handguns, all the same brand (Glock), which I've come to know like the back of my hand.
A pistol is only for when you can't carry a rifle.
What I mean to say is that for home defense, where your options are wide open, a pistol should only be considered backup. My preferred choice is a Remington 870 Police Magnum 12 gauge with extended magazine and low recoil personal defense shells. No fancy add-ons.
In action (it's a marine magnum, same thing - nickle plated for extreme conditions).
https://www.youtube.com/watch?v=n2fb1VIiRYgIf you plan to use any weapon for self-defense, consider professional training! It's really unbelievable how much you can learn. I've been around firearms all my life, and I'm still learning.