How to replace rear adjustable sight on S&W Revolvers

[mikemyers]

The reason I'm asking this, is because the original adjustable rear sight on my Model 28 didn't seem to be working properly - turning the elevation screw didn't seem to be working, and when Will at the Sebastian Ammo tried it a month or two ago, he thought something was wrong. He sold me a used one he had in the shop, and I assumed they were all the same. Now that I know more, I realize that these sights come with different blade heights, and the blade on the new sight is much higher than the blade on the old sight. I need to lower my sight such that the grouping is about an inch and a half lower at 15 yards.

The main reason I'm posting this, is because I want to know how to properly remove and re-install the complete sight assembly. Jerry's book has LOTS of information about the adjustable rear sight, but doesn't say much about how to remove the assembly (possibly because it's so obvious - remove that front screw, and it looks like it will come right off).

I did some searching on the internet, and only found one place where this was discussed:
http://thefiringline.com/forums/showthread.php?t=262256

Instructions there say:

• To remove the entire sight, turn the elevation screw to raise the rear sight, and take some of the strain off. DO NOT back the screw all the war out.
  
• Remove the screw at the front of the leaf and slide the entire sight backward and off the frame.
  
• When reinstalling the sight, you have to fit the tiny square nut on the bottom into the "T" slot on the frame.

It all sounds so simple, but the words I marked in red sound backwards to me - to remove the strain in the sight, should the rear of the sight be lowered, or raised? If it comes "flat", it would make sense to raise it, but if it comes bent upwards, and it's adjusted by forcing it down, then these instructions would make sense as written above.


Second question - before I put the old sight back on, as now that I've cleaned it out a little, it seems to be working - any suggestions on cleaning it best while it's still assembled, or do I really need to take everything apart? Unless I have to, I'm not sure I want to deal with those tiny springs that work with the detent mechanism.

 

[Zaydok Allen]

You are over thinking it man. Righty tighty, lefty loosey. Raising the sight by unscrewing it (lefty) will relieve strain.

As far as cleaning goes, I have never completely removed my sight to clean it. I just use Hoppe's #9 liberally and let it penetrate into the crevices and push out dirt. Then I swab it out with a Q-tip.

Don't make it harder than it needs to be.

 

[BobWright]

If, as you seem to indicate, the elevation screw threads are stripped, don't worry. Simply remove the small screw located in the tang of the sight. Then slide the sight assemble off towards the rear of the gun.

To install the new sight, slide the little square nut into the mortise in the frame, then replace the retaining screw.

You are fortunate if the sight blade is too tall, as you can file it down to sight in. Its best to have your rear sight about midway height when doing this. File until your groups are where you want them. Afterwards, touch up the filed area with cold blue.

Bob Wright

 

[BCRider]

That does seem odd so it might be a misprint. But just keep that in mind. After you remove the front fixing screw try it according to the instructions and if it doesn't slide out easily then do it the other way.

The trick is to keep the mind awake and analyzing things like this as you're doing the tinkering.

 

[rcmodel]

Mmmmm?

I'm not sure how it can slide out with the elevation screw in the way.

Loosen the elevation screw all the way to release the sights bowed base spring pressure..
Take out the front screw.

And lift it straight up out of the mortis in the top strap.

rc

 

[BCRider]

... which answers my secret question about the sight's base being bowed or not. So yeah, it'll be removing the screw to let the base arm bow upwards to its relaxed position.

 

[dmurdach]

Cleaning the sight

To answer the question on how to clean the sight with it still in place, I would soak it in my preferred cleaner and then blow out all the nooks and crannies with an air compressor, then oil.

Dave

 

[mikemyers]

Just to clarify - if my original sight just needs cleaning, it's now off the gun. It seems to work OK while off the gun, but I don't know if the threads are damaged, meaning under pressure it might not work. It didn't seem to function correctly for me or for Will, so we replaced it. I plan to clean it and lubricate. I don't know about completely disassembling it, as the S&W manual shows lots of little parts to be concerned about, but I guess it would be good to learn that stuff now, since I have the other one on the gun.

In retrospect, I think I was wrong, but I always envisioned the rear sight as being "flat", and as you turn the elevation screw, it would raise up the back end of the sight. Looking at my old one now, it is not flat - it's bowed, with the rear of the sight already up. That means the explanation I thought was wrong, is actually correct - the un-tensioned sight would be high, and the elevation screw would pull the back end of the sight downwards as it was being adjusted.

In that case, the right thing to do would be just what that explanation says - allow the rear of the sight to come up quite a bit, which is taking the tension OUT, and then remove the front screw.

You are over thinking it man.

For better or worse, that's the way I do things. I'd rather think about it for however long it takes, and then do it right, than take a seemingly obvious guess, and make a mistake. That's why I posted the question here.

 

[rcmodel]

You can take the elevation screw out of the sight to clean it.
But I wouldn't recommend it.
There is a microscopic spring & plunger in there that can disappear in the blink of an eye.

You cannot remove the windage screw and sight blade without breaking the windage screw off.
Then replacing it with a new screw & staked nut when you get it back together.
And there is another microscopic spring & plunger in it too!

I don't recommend you do that either unless there is no other option.

rc

 

[BobWright]

The elevation screw is a female thread, the square post has a male thread. The elevation screw raises or lowers on that post. The square stud slides out attached to the rear sight assembly.

Bob Wright

 

[Zaydok Allen]

That's why I posted the question here.

I meant no offense. It's better to ask if you're not sure of course.

 

[mikemyers]

Hmmm, it isn't that I would or wouldn't take offense, it's just confirming what you wrote. I almost always over-think things, and not just here - all over. I can't help it, it's just the way I am.

Sorry if I made you think I was taking offense, or anything - even if/when people do try to offend me, I don't take offense. To me, THR is a huge, live, resource, a goldmine full of useful information, and with lots of warning signs of things one ought not to do.



As a temporary "fix" until I can do this correctly, I switched to using the sights "lollipop style", so I'm aiming low and the bullets are going closer to where they should go. I'll either file down the sight blade of this new sight (which has the white outline), or see if I can get the original sight (black sight blade) working properly.