I started this post as a comment to Hsoi's post over on Stuff From Hsoi. I soon realized that the comment rivaled the original post in length, so it warranted a post of my own. You should probably read it first to get a context of the discussion.
For what Hsoi posted, I'll agree for the most part - with the stipulation that this deals with new shooters. Honestly, an optimal solution would be to make sure the new shooter gets enough range time and shooting experience to make a logical personal choice on his/her own. This not being an ideal world, we end up in a lot of discussions as to what weapon would be best for these new and inexperienced folks.
I've got a Remington 870 18" 6+1 shotgun as my primary home defense gun. I practice with it frequently, to the point where I am quite confident that I can put all my shots squarely on multiple targets while moving and shooting.
The rub of the shotgun for the uninitiated is the recoil, and practicing enough for its operation to assimilate it into muscle memory. Not long after I got mine, I took my girlfriend to the range so that she would know how to operate it if the need were to arise. Unfortunately, the only range option that day was Red's. As those familiar with the range know, Red's has the usual restrictive rules of typical indoor ranges, and I was informed that we could only shoot slugs. This does not make for a happy introduction to the shotgun for most first-timers. She only put a couple of rounds through it and decided that was enough. Not good when you want someone to be intimately familiar with a defensive weapon.
To deal with this problem, I later replaced the rear stock with a Knoxx SpecOps stock. The difference it makes in felt recoil is amazing. This particular stock provides an M4-type 5-position adjustable/collapsable stock with a pistol grip. Additionally, it has two sets of recoil compensators that take all the bite out of shotgun recoil. I tested it out at the range and found that 3" Magnum slugs approximate felt recoil of a 2 3/4" bird hunting load. It's really that spectacular of a difference. What's more, follow-up shot delay is shortened to however long it takes you to rack the slide - the normal muzzle rise and operator movement experienced with heavy defensive loads is marginalized to the point where the sights remain on target after recoil.
In addition, Blackhawk makes an add-on shell-holder/cheekpad kit that provides on-gun storage for an additional 5 rounds. The "low" cheek pad provides the perfect cheek weld height for shooting with the bead sight (the "high" pad is made for rifle-type sights or optics). My girlfriend has picked up on my enthusiasm for the recoil-reducing capabilities of the stock, and has promised to give it another try the next time I can get her to the range.
I've taken it skeet shooting, and found that quick sighting on moving clays to be very natural and effective. This was only my third time shooting skeet, and I managed to get a score of 14, shooting doubles.
As for the "racking the slide" deterrent discussion, I bought into this initially. After thinking about it logically, I came to the conclusion that this was tactically unsound. Any element of surprise I can get on an intruder benefits me and my loved ones. The shotgun lives with one in the pipe these days, and the only sound it's going to make is a little "click" from the safety disengaging.
I agree with Hsoi on semi-auto vs. revolver. Practically, the issue comes down to what a person is willing to shoot with. My girlfriend is much more comfortable with the idea of a revolver as a personal defense weapon, and has favored them at the range when trying them out. For her, the operation is straigtforward and easy to understand, so she's simply more confident with them. That's the most critical part of the equation - whatever your choice in defensive weapon, you have to be confident, willing, and ready to use it.
Personally, I agree that more rounds available is better. I do, however think that the devistating effect of 9-12 (depending on your load of choice) simultaneous 00 buckshot pellets in a defensive 12ga makes the shotgun my #1 pick for home defense. I am confident of this because I've put in the time and effort to practice with it in varying scenarios. I do keep a high-capacity semi-auto as backup, should circumstance warrant it.
As for new shooters, it really depends on the individual. Generally, I will recommend a shotgun for a few reasons.
Long guns in general are easier to be accurate with, and my experience has shown me that muscle memory learned on a long gun (and shotguns in particular) is retained far longer than with a handgun. This is helpful for the individual who wants a weapon for self-defense but doesn't go to the range all that often.
Secondly, shotguns are cheap and require relatively low maintenance. Ammunition is relatively easy to find, especially given the recent run on handgun and common rifle ammo. This means that a defensive shotgun and ammunition can be acquired quickly and more readily on a tight budget. These days, that's an increasingly important factor.
Lastly, there is the firepower factor. A shotgun is simply unmatched when considering how much damage it can inflict in a close-quarters defensive scenario with a single pull of the trigger.
I'm no expert, and just about any choice a person can make for a defensive firearm is better than nothing. Again, the weapon you're willing and able to use is what you should go with. If you think revolvers are the bee's knees, then by all means go with that. The universal suggestion I give anyone asking about a self-defense weapon is to practice with it, and know it well.
Hsoi has updated his post with a couple of points in response, and I'll address those here.
Just to clarify, the above mentioned range trip with the girlfriend wasn't her introduction to shooting. We had made her introduction something like a year prior, with a good friend and experienced shooter doing the instruction. For her first range trip, we started her on a Ruger Mk II (.22) pistol. She worked her way up to some revolvers and semi-autos in .38 and 9mm. We also touched on rifles with a nice little .22 he had. She'd also been to the range another time before the trip to Red's. As you noted, starting off with something light and easy to shoot is critical with new shooters, and this is my standard practice. I have a Walther P22 and a Marlin Model 60 that I purchased specifically for this purpose.
I also agree that indoor ranges are a bad place to introduce someone to shooting. I never have and will not take a new shooter to an indoor range for the reasons Hsoi listed. Also, they're no fun because of lane restrictions (which make it difficult to instruct), the noise, and time constraints due to hourly rates common at most indoor ranges. In fact, the only time I'll go to an indoor range is if I'm meeting up with another experienced shooter who can't make the long trip out to the outdoor range.
This trip was, however, her introduction to shotguns, and I was unaware of the restrictions on shotgun ammo in place. I'd brought along plenty of light #4 Buck loads for use on our trip, and ended up unable to use any of it. Being on a time constraint, I tried to make the best use I could from the situation. The result was negative, and I've learned from the experience. Put in the same situation today, I simply would not have gone to Red's at all and scheduled a trip to the outdoor range for another day.
As for our disagreements on what's best for a new shooter, I'm cool with that. As posted above, the weapon you are comfortable with and will practice with is what you should use. If someone is more inclined to get a revolver, pistol, or rifle over a shotgun, that's fine by me. I'll point out the strengths and weaknesses of any weapons system so that person is able to better make an independant and educated personal decision. As an example, while a M4-style rifle (as Hsoi suggests) is appropriate for some people, others who have apartment neighbors to consider might find that a rifle presents too high a risk of third-party injury or death; Handguns allow one-handed operation, so the weapon is at ready when opening doors or for defensive hand strikes at extremely close range, but are more difficult to make quick and accurate shots with under stress.
As Hsoi also noted, a plan is essential for effictively defending your home and loved ones. Evaluate your options, know where your line of fire will be in relation to where your family members and neighbors are. Come up with plans for as many possibilities as you can. I take these factors into consideration when running drills at the range. This can mean taking kneeling or crouched shots against an intruder, shooting from your weak side, shooting one-handed, transitioning to backup weapons, reloading, drawing and shooting from a seated position, failure drills, etc. The more you know and have trained for, the more options available to you under the stress of a life-threatening situation.
Thanks for the response, Hsoi.