"..Fully adjustable sights are more fragile, and can break at times. They're great for range shooting, but not-so-great for hard, heavy use...."
I supose "more" fragile may be the case, but in the time I've spent abusing sixguns, and one Colt National Match auto, I've not managed to seriously break any of them, at least to the point of being unusable. I had one Blackhawk lose it's elevation screw from a poor quality Hunter holster that pushed on the sight to the point it left no tension on it (a sight guard tab in the holster prevents that, or a holster designed so that the sight is clear of the holster body), and the screw came out. This is a holster issue more than a gun issue, but even then the gun can be adjusted so it isnt likely to happen even in a poor quality holster. On later Blackhawks, I've adjusted the rear down a few clicks up from bottom, and filed the front down close, ans reshaped it. I then fine tuned the rear for sight-in, this leaves tension on the elevation screw, and looks better. The gun in question was a 357 and it was almost topped out in elevation adjustment to sight in. I feel the Ruger sight design is OK, but this is its weak point, and is managable when needed. The Smith rear sight is better in my experience, as it's always under tension and I've never had one get out of adjustment, including several years of carrying while riding old Harley's, with a couple slides on the pavement etc. The adjustable sight I did actually damage was a Smith 29. I dropped it out of my belt while camping, climbing out over my truck tailgate. It fell
on the rear sight on the angle iron bumper, and cracked the rear sight blade. No problem with zero, just that the blade was a little askew on one side. I can't recall how many other times I've dropped that gun on various surfaces without the sights being affected.
I'm a believer in adjustable sights. I simply havent seen the "fragile", "easily damaged" or knocked out of zero that I hear about from others. I'm sorry for you fellows misfortune with your sights (those that actually had it happen, not just repeating what you've heard), I simply havent had it happen with my guns in the 30 years I've carried fairly heavily, and what many would term abuse of my guns. The majority of the fixed sight guns I've had or shot didnt hit exactly where I wanted them to. I may not touch the adjustables for an eternity after sighting in with the load I choose to use (notice I didnt say with the load the gun shooses, or someone else chooses), but I know when I pick it up, it hits exactly where I want it to. I
dont want to have to mentally calculate which gun I have in hand, where to hold to make a good shot, how to hold my hand or trigger finger on that particular gun to get it to shoot to a particular point of impact, etc. If one cares for that sort of thing, that's alright, but I don't care for it. Maybe I'm doing things wrong, but I seem to do it consistantly, and am happy with my results for the most part.
Years ago, I used to think about what it would take to make an adjustable sighted Ruger into a fixed sight gun, for many of the reasons I see in these threads. Years later, the Vaquero's came out, and I have a couple. After using them for 15 years or so, I'm now looking at them and thinking what it will take to get Smith K frame adjustable sights on them. The gunsmith is looking for his elevation seat mill cutter needed to do the first one.