Mr. Borland, please expound on your reasons for the dash-5 items and why you prefer them. Always looking to improve my playbook.
Sure. Keep in mind, though, that my 686s are my IDPA guns, so these personal preferences (and they're just that) are guided by that. IOW, folks, let's not turn this into a "new vs old S&W".
pre-lock: I'm no Lock-hater, but I'm no fan, either. My 1° 686 (a -6) has The Lock. That's Life. And IDPA rules prohibit it's removal. That's Life, too. Yet, it (the gun) has performed flawlessly. Nonetheless, it's a mechanical part for which I have no use, so all else being being equal, I'd opt for the simpler design of the -5.
frame-mounted firing pin: For one thing, I convert my match guns to DAO, with as light a hammer as possible
*, and hammers with the FP attached can't be made as light as those without. Randy Lee, for example, known for his incredible tuning of DA revolvers, makes a terrific DAO replacement hammer, but only for guns with frame-mounted pins.
Also, if either FPs break, a frame-mounted pin (or spring) is
much easier to replace. In fact, if you carry a spare (and a screwdriver), you can do the swap in the field in a few minutes. Not only can you
not field-replace the hammer-mounted FP, it's generally enough of a PITA that most will have a gunsmith do the work.
Finally, aftermarket frame-mounted FPs are available which are slightly longer, and claim (don't have the data myself) to improve reliability of match guns that have been tuned close to their lower limit. I'm not aware of any aftermarket hammer-mounted pins for über-tuned guns.
pinned front sight: The front sight on earlier versions (up to, and including -3s, AFAIK) is integral to the barrel, so replacing it involves some machining by a gunsmith. I feel there are better front sight options that the stock red ramp, and a pinned front sight makes the swap much easier, even if a gunsmith does it.
new style cylinder latch: I just like them better than the old style. Better ergonomics, and less interference with a speedloader, IME. Truth be told, in 2 cases, I've replaced even the new style latches with aftermarket latches from SDM, which are visually indistinguishable, but are much grippier.
You could also have it converted to use moon clips, if that's something that interests you.
Yeah, you could, but be aware of 2 things before making that leap:
1. Moons work best with short, fat auto rounds, such as .45acp & .40S&W. Loading relatively long and skinny revolver rounds from a moonclip can be like pushing spaghetti. Also, moons for revolver rounds are thinner, exacerbating the spaghetti effect, and are more easily bent.
2. If you ever get the itch to compete in a local IDPA match, conversion of the cylinder will take you out of the natural home of the 686 (SSR) and into ESR, even if you don't use moonclips. Most local matches probably won't even know the difference, and even if they did, they'd likely let you still shoot SSR if you use speedloaders. Even so, I've never found enough advantage to the conversion to do it. If I wanted a moonclipped .357, I get a 627 for the 8-shot capacity, and shoot gamer .38 Short Colts from it.
(so IDPA-illegal, I wouldn't know where to start explaining why
)
* and pre-lock hammers on IDPA guns can be made even lighter since they don't have to retain the locking flag.