Agreed, but in this case the action with the least parts is the old "4 click" Colt style. It has the least parts but uses the least reliable forms of springs.
Wear that leads to timing slop was also mentioned. But both SA and DA/SA revolvers rely on the same sort of parts to move and lock the cylinder. So I don't see an advantage one way or the other. With wear or peening both will produce a bit of rotational cylinder shake.
Axial shake is also of concern. Of the DA/SA hand ejector styles I've seen there are a lot more parts in the cylinder arbor assembly and an often surprisingly delicate crane that supports the cylinder. The SA style dumps all this for a nice solid pin held in a nice solid frame. So advantage SA in this case.
That leaves us with the internal action components. But in looking at the internal schematics of various revolvers other than the old style original Colt action it's clear that the parts count is pretty much the same.
So all in all if the guns are handled with normal care I don't see one being better over the other. But if we include rough handling and possible crushing or drop strength then I'd say the nod goes to the more solid construction of a SA revolver. In particular the models with the shorter barrels since that gives any forces a shorter lever to work with.
For simple parts reliability I'd say the materials and techniques used by the maker over the actual design are more important. And with that sort of care comes a higher cost. So all in all I'd say if you bought USFA or Freedom Arms you'd be getting about as reliable a gun as you'll find. It's just a coincidence that these are both SA styles.
Or perhaps a Korth? Another gun with a stratospheric price which by rights SHOULD mean that they use only the best materials and best control over the heat treating and fit.
On the other hand how many shots have been taken from the lowly S&W model 10's over many, many decades of use? Can one of these even become worn out from shooting the fairly gentle .38Spl loads? What about the round count through various S&W Model 17 and K22 revolvers? How would these compare to guns that shoot a steady diet of larger Magnum rounds?
And then there's the issue of how the guns are used. It's no secret that rapid firing of DA revolvers involves a high impact force on the cylinder stop bolt and the hand as the cylinder is quickly indexed and stopped with a SNAP. It's also pretty well known that holding the trigger down and fanning an old style SA revolver is a good way to beat the action out of proper timing. So perhaps we need to factor in the power of the cartridge and how the gun is used?
For example I don't see a big difference in the stop bolt and hand used in a K frame S&W to a N frame. But the cylinder on a Model 27 or 28 is bigger and has a lot more metal in it than a K frame model 10 or 19. So that poor stop bolt, frame and cylinder notches have to suffer through far greater impact forces when being shot in a rapid fire DA mode than the smaller and lighter K frame parts.
If the cylinder is anything but perfectly timed and locks up with anything less than perfection the cylinder notches, bolt and hand will also see some impact loads. So shooting lower power ammo such as .38S&W, .38Spl and .44Spl should result in less deformation damage over time. So this could also come into the picture.
So all in all perhaps we need to look at the WHOLE picture. In which case there's a lot to be said for a Model 10 or Model 14 in .38Spl shooting a steady diet of 148gn HBWC loads. Such a gun shot with that sort of ammo would easily outlast any one owner. Or the .22LR Model 17 or K22. Lots of examples of these are still in like new condition even though they might be 30 to 40 years old and have seen many thousands of rounds sent downrange.
The bolded sentences are one of the biggest differences IMO between DA and SA revolvers.
In terms of abuse, the two biggest causes of death among old police or military DA revolvers such as the S&W New Centuries and Model 10s and the Colt New Models and Police Positives were total neglect and macho reloading.
They are also the two biggest issues that must be watched for when buying old DA military or police surplus revolvers or their civilian equivalents.
The neglect one is obvious: a revolver would be turned into the police armorer because 'something is wrong with it and it won't work right'. And the armorer would find the weapon was rusted solid after being left untouched in its leather holster from one annual qualification day to the next - even on the days when that holster got soaked by rain or snow on the beat... T
he macho reloading problem is in some ways more serious, although less obvious to spot. Its symptoms are a torqued cylinder crane resulting in a 'sprung cylinder'. I personally believe the main cause of this problem is that far too many users developed their reloading technique by watching those old Hollywood gangster or war movies and early TV police dramas. In them, the macho hero would almost invariably 'check his revolver' before the battle by opening the cylinder to check it was loaded (or to reload with fresh rounds) and then shutting it again. The problem was, as a macho screen hero (or villain), he had to do this
with style and panache.
He couldn't press the cylinder latch, then
ease the cylinder out with his fingers, cradling it in his other hand, and close it again the same
gentle way. Oh no! Not a screen hero!
He would open the action with a sharp debonair leftward flick of the wrist that whipped the cylinder out until the crane slammed to a stop at the end of its travel. Then, after glancing at the cartridge bases in the cylinder, he would close the gun again with a well-practiced rightward snap of the wrist that slammed the cylinder back into the gun again.
All that manly flicking and snapping of the wrist demonstrated supreme macho competence and familiarity in handling a revolver to the viewers -- while torquing the hell out of the revolver's cylinder crane. The weight of the cylinder is not only at the end of the crane but entirely to one side which creates twisting leverage on the cranes pivot point. Which, over time, quite understandably warps and screws up the delicate alignment between the chambers and the barrel...
The only way a macho twit can possibly subject the cylinder and lockwork of an SA revolver to anything remotely equivalent to the stresses created by hard, unsupported opening and closing of a DA revolver's swing-out cylinder is if he decides to pound nails with his revolver - and uses the side of the cylinder as his hammer instead of the butt...
