In my youth nearly all the police officers I ran into carried a revolver, the vast majority of them a .38 or .357 Magnum revolver. My uncle was a police officer in Colorado and his was the first magnum revolver I recall seeing. It was a thing of beauty; a 5" S&W Model 27, though it was probably what is called a "pre-model 27" today as I am pretty sure he had it in the mid 1950s although I did not get to actually handle it until around 1960. It was stolen from his house after he was tragically killed by a drunk driver so I will never get to shoot it and don't think I have any pictures of it in our family albums.
That became the Holy Grail for me as a kid. I wanted to own a magnum revolver. It was a long time before I even heard of different magnums like the .44. Like all young boys I also wanted to own a Colt Peacemaker. By the time I was 9 or 10 I must have vanquished 10,000 bad guys with my Mattel Fanner 50!
I managed the Peacemaker, sort of, first. It wasn't a real Colt nor was it a "man-sized" caliber but imported copies of the .22 Colt Scout were available for around $25 and I picked up one of those and spent a few years wearing it out on the weekends.
My first centerfire handgun was a Remington Rand 1911a1. I wasn't that enthusiastic about the design back then but again the cost was a huge factor - it was cheaper than even a used DA revolver.
Finally came the day when I had enough money to purchase a brand new K-38. I was shocked on my first outing to find out that revolvers weren't as reliable as I had been lead to believe; my new toy "jammed" on the second cylinder full. It was my fault but it did reveal that wheel guns can be finicky. You see I didn't know any better and I pushed the ejector rod back after the first cylinder full and plucked each round out of the chamber so that I would not have to bend down and pick up the empty cases. Unbeknownst to me some flakes of unburned powder found their way under the ejector star. That caused the ejector to rub against the breech face. It got worse with each pull of the trigger until about the 3 round I could not rotate the cylinder anymore and I could not open the cylinder either. In desperation after some minutes, I located a plastic hammer and beat it open.
One thing is for sure, after learning about the powder thing, my new revolver was far more accurate than my old rattletrap Remington Rand. I had something to learn there also but it would take me about 10 more years. That Remington wasn't really inaccurate but I sure didn't know how to shoot it!
Back then the most use I had for a handgun, other than plinking at tin cans, was hunting small game and varmints. I was already a handloader so I added .38/.357 dies and started loading some souped up light JHP bullets for woodchucks and some wadcutters and semi-wadcutters for small game like rabbits and squirrels.
I've had many wheelguns since that first K-38 and I have to admit, though I became a dedicated 1911 fan, I have never been without a good wheelgun since then. Today it seems that many "experts" want to just ignore the class of handguns that have the "twirlly thing" and even some autos that don't hold a week's worth of ammo.
I admit it is hard to brush aside the benefit of having plenty of ammo on board but at the same time if we examine just what is required of a self defense handgun we will find that one usually runs out of time before he runs out of ammo, at least in the "normal" lethal encounter - whatever normal is.
It is true enough that we often, too often, see cases in which many rounds are fired which do not bring about the desired result; stopping the attack, but they are not all that common, perhaps one or two cases in ten. But the times when a really well placed bullet that penetrates deep enough has failed are pretty rare. I do not mean the typical "center mass hit" - those fail quite regularly, but a bullet that hits the central nervous system is a pretty sure bet.
In my research, I find that if you practice a lot and at the ranges in which the vast majority of these things happen, a cool head can obtain such a hit in 2 or 3 rounds.
While I found out early on that revolvers were not necessarily more reliable than a good auto pistol, they are never-the-less pretty sure to work for 6 rounds. Also they do not require bullets of any particular shape to work. If you plan on reloading it fast then it might take a bullet that is pointier.
To me the biggest disadvantage to a wheelgun is that you have to take it completely out of action to top it back off to full capacity. We don't often reload a weapon during a fight, but we would be well advised to top it off as soon as we can after the fight... for another fight be coming our way in the short term. Over the years I have become convinced that the answer to this problem is to carry two revolvers. That is hardly a new idea. It goes way back to the first revolvers. It was reinforced in modern times by folks like Jim Cirillo of the NYPD Stakeout Squad. For that reason such a practice is called "A New York Reload".
Probably the most commonly thought of revolver for self defense is the quintessential 5-shot J-frame S&W or one of the copies of same. I really like these guns myself but I would caution you that they are very difficult to shoot really well. To be sure, they can be quite accurate. However wringing the needed practical accuracy out of them is difficult at best. It takes a lot of practice to be able to shoot one with the necessary shot placement given their limited power.
Tempting as the small wheelguns are it may be better to look to something just a bit easier to shoot well. The quintessential service revolver is the 4" S&W K-frame or the Colt D-frame, both of 6 shot capacity. Both are eminently concealable if you have a proper holster. Three inch versions are also available and those quite often are an excellent compromise. They are far easier to shoot well than a 2" revolver.
The attenuated barrel length does have a slight effect on power but not as much as one might think. In the old days of expanding bullet design cutting back 2" of barrel might result in poor expansion but these days there are some good designs that expand fairly reliably in short barrels. That said, the dirty little secret is that only about 1 out of 3 bullets fired in the real world expand from a handgun.
The .38 Special is certainly no power house but, truth be told, neither is the .357 Magnum. Still, if your bullet holds together and you place your bullet well, a .35 caliber slug of between 125 and 200 grains is likely to suffice.
You can improve the odds of success by choosing a larger bore size. While some esoteric options exist, the more common calibers you will find are .41, .44 and .45 nominal diameters. .44s are actually .43s of course.
While the .45 Colt was the clear choice of most of the 19th Century gun hands, the .44-40 enjoyed an excellent reputation for stopping. More than one old timer has commented that this might be because of the standard flat pointed bullet. While it weighed less than the .45 Colt in either the military (230 grain Lead Round Nose) or the "civilian" load (250 grain Lead round nose or small flat point), the flat on the .44-40 was noticeable. 200 grain .44 bullets seem to have enough penetration for people sized targets and even deer, large game might be another thing.
The .44 Special is a fine defensive cartridge and there are several modern loadings which make it very attractive. The Speer Gold Dot 200 grain load is excellent and performs much like the 230 grain JHP of a .45 Auto. Hornady produces both 180 and 200 grain expanding bullets that are very attractive. Cor-Bon also produces modern JHP ammo that will both expand and penetrate.
While the .44 Magnum isn't totally absurd not very many people can master the full powered loads. One possible alternative is the Winchester 210 grain Silver tip which is not really a "full powered" load and is fairly manageable. Smaller manufacturers sometimes offer good "mid-range" loads for the .44 and .41 Magnums. Look for moderate velocity loads from Buffalo Bore, Underwood and Georgia Arms, etc.
You can get 5-shot .44 Specials that are no bigger than K or L-frame S&W revolvers. Some of them are not all that well made but they are still an option. The S&W 696, a 3" L-frame is out of print but if you are lucky you might find one.
Personally, I have carried a 4" and even occasionally a 5" N-frame. With the right holster they aren't that hard to conceal. S&W even makes a very lightweight short version of their N-frame Scandium revolver and it weighs very little. And there is a LOT to be said for putting a .45 caliber hole in something.
The .357 Magnum enjoys a good reputation for self defense. While I haven't found it to be in the class of .45 Auto or .45 Colt on 200 pound game it will still get the job done, though it is a bit harder to master for the novice when it comes to speed and accuracy. It will still get the job done most of the time just don't expect miracles with any handgun.
One thing is for sure, a Colt Python is a thing of beauty and, with the exception of 5 individual samples or some custom guns, they are only available in .357 Magnum. Shown below are a 3" Python (a bit more rare than a 2.5" model) and a Custom S&W M-19 the author carried for uniform duty in Memphis during the 1970s. It was built by a Police Armorer... things were different back then.
While it is great to get as much advantage as you can when it comes to self defense the primary things that will affect the outcome are still more related to your skill and your mindset than they are your equipment. Don't overlook the wheel gun when you are considering your options!