Hello All,

I picked up a no-dash 686 last weekend for a decent price. It's only issues are a little bit of light marring on the side of the cylinder, and a botched rear sight replacement.

A former owner apparently replaced the rear sight with a Meprolight night sight, but in the process apparently lost the detent plunger and spring. They also opted not to stake the nut in place, so the whole assembly is just screwed together for the moment with no real ability to adjust windage, except to take the whole leaf and screw out, turn it a little one way or the other, and screw it back together.

Since the sight has very very little glow left, I went ahead and ordered a standard 0.146 sight leaf, a new plunger and a new spring, with the intention if replacing everything back to a stock configuration. I also ordered the correct spanner bits from Brownells, as I didn't have them. I watched a couple of how-to videos on YouTube about the process, but in am curious to know if any of you who are seasoned sight replacers have any tips for a first timer? Mostly I'm concerned about the staking process. Is there a right way and a wrong way?

Thanks!

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It helps to have a third hand, like a small padded bench vise or similar to hold the sight body while you are working. If it's a small vise, you could actually lay it on it's side on the benchtop, with the sight assembly protruding out the side. You just need another hand, not necessarily a completely "inflexable" one. Many recommend placing a clear plastic bag over the work when you are attempting to install the spring loaded plunger, sight blade and screw back into the cavity in the sight. If there's a mishap, the launched parts will hopefully be caught in the bag, and not fly off to parts unknown.

Prior to staking, you'll need to back up the head of the screw with something hard, like a "non-marring" bench block. You can stake the center of the windage screw with a center punch, or a small bladed screwdriver who's dimension is slightly narrower than the overall size of the nut, and thin enough for the blade to fit into the slots in the nut itself. If you use the screwdriver method, you are basically just trying to move enough material into the slots to prevent the nut from backing out.
Prior to staking, tighten the screw and nut together, and then back off the screw approx 1/4 turn while holding the nut still. This will allow the entire assembly to turn as a unit after staking, but have minimal side to side gauge or "slop".

One of the members here suggests shooting before staking which is a great idea.....but if you are replacing a known blade height, that shouldn't be necessary.


Here's a close up of a couple of factory staked screws in the assembly. The factory ones tend to be a bit "over-staked" at times, IMO, almost like they are hit with a blade and a center punch.

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Ret. LE, FA Instr, S&W Armorer

It was my understanding that the rear sight height was determined by barrel length and revolver model. After doing some digging here and elsewhere, it seemed for my 4" 686, a 0.146" sight leaf was correct. Is this not true? It leaf height determined at the factory for each individual revolver?

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Well, yes and no. My parts book shows the 586 and 686 (-3 versions) with 4 or 6 inch barrel as using the .146" height blade most often.....but there are some other height options, like a .160" for example, for other dash numbers of the same model (686) Perhaps it would be best to shoot the gun prior to staking if that's feasable.

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Ret. LE, FA Instr, S&W Armorer