Ever file the rear notch to adjust a fixed sight gun?

[tacotime]

Got an old 2 inch Mod 36. Finish is badly worn but the action is solid. Shoots about 4 to 5 inches left at 25 yards. I know that's fine for shooting bad guys in the house but I like to target shoot with this little guy, and out to 50 yards even.

I can file the rear notch on the right side a little to move the point of impact, and to widen the notch, which would make for better sighting anyway. I wouldn't do it on one in better condition, but it can't hurt this one.

I started with a flat diamond file. The going is slow and tends to lightly scratch the bottom of the notch, not wanted.

Is there a good way to do this that won't bugger the notch?

 

[airman]

Just an idea. Glue, or grind away, the edge of the file so it won't scratch.

 

[tennexplorer]

Airman is right. The file needs to be made safe on the side you are not using. I would also recommend turning the barrel in slightly. With that short a barrel, you will not have to move it much to move the point of impact the amount you need. Probably only about .02 inches.

 

[David Sinko]

As you describe it, the point of impact in relation to the sights is unacceptable, even for a J Frame. I was going to suggest milling off the front sight and cutting a dovetail for a new one which could then be adjusted for windage, but I see you've already gone to work with the file.

Dave Sinko

 

[tacotime]

Good idea about the glue. I went to smooth the bottom edge of the file on the grinding wheel, but of course since it was a diamond file, it began to wear a groove on the wheel, so I stopped, with the file apparently unchanged. Glue is the answer there.

The barrel is pinned... so no turning, that would be above my courage here.

I would have thought someone makes an adjustable rear sight one could install on these frames, but I have not seem one, or one that was reasonably priced. And I believe that would also call for a taller shark fin front blade, like the 34-1.

Next idea - the small cylindrical diamond bits for the dremel. I realize care is needed, then finish with a flat file and #800 paper, and cold blue.

Anyone have a guess as to the amount of metal that needs to be removed?

Or from another angle, if this gun would have had the usual S&W adjustable revolver sights, how many clicks would have been done to move the POI 4 inches right at 25 yards? Then I could get an idea how much we are talking. Guessing from experience, maybe 3 or 4 clicks?

Gotta say, this is good fun... thanks.

 

[Fat Old Guy]

Could it be operator error? Not being a smart ***.

 

[Bert Man]

Tacotime, have you tried different ammo to see if that makes a difference? Different brands/bullet weights often don't have the same point of impact on the target. To minimize human factors it often helps to test fire from a padded rest on the bench. Also, not to impune your marksmanship skills, but have you had another shooter fire the gun and see where it prints for them? If their shots are near point of aim then it probably isn't the gun. If another shooter, however, gets the same result as you then either the sights aren't regulated properly or the barrel may not be perfectly aligned in the frame and judicious filing of the rear sight notch may correct it.

If it was me, I would not do any filing until and unless the above checking has been tried first without sucess and I definitely would not bring a dremel tool anywhere near my S&W. If any filing is needed it
would be thousanths of an inch and I would only do it by hand filing very lightly and checking for changes as I went by re-firing. You can always
file more off but you can never add any metal back on once it's gone.

Regarding S&W revolvers with adjustable rear sights, One click will move the bullet strike approximately 1/8 inch at 25 yds. Hope this helps.

 

[tacotime]

Thanks.

Yes - other ammo has been tested with the same results.

No - no one else has shot the gun but the shooter shoots his other 2 in. Mod. 36 on the bullseye at the same distance with the same loads.

I was thinking the adjustable sight clicks moved the POI more, but you would better know the specs. Correcting the 3.5 inch off center would call for a lot more clicks than I was expecting!

In any case, very small amounts will be milled between test firings. The backstop here is that if too much was removed from one side, some could be taken from the other side to re-center the sighting, not that I want to use that remedy.

 

[mstuhr]

Go after the front

Howdy,
It seems to me the front sight would be the place to whittle on.
In the event of a massacre you could still screw another barrel on.
I'd get me a good clean file and sneak up on the front post while at the range.
Good luck
Mike

 

[Pisgah]

Are the grips the same as on your other J frames? I ask because
I have seen a grip change immediately fix -- or create -- the same problem on several I have owned.

 

[tacotime]

Grips are both standard J frame RB wood...

Does S&W screw new barrels into old pinned frame guns? If so, do they pin them?

 

[k22fan]

I can only offer a few random comments that may or may not be of any help. The shorter the sight radius the larger the POI will move for the same amount of movement of a sight, so how far a click will move POI varies by barrel length. If the factory considered the revolver to be at fault their method of correction was to whap the frame with a babbit bar. I don't know if they still do that but Brownell's still sells the babbit bars. I wouldn't try this myself. I imagine it would take a lot of trial and error to learn how hard to whack. I think the best solution would have been to have a gunsmith rotate the barrel a little to offset the front sight. That requires a frame jig or clamp and a barrel wrench.

 

[tacotime]

Rotate a pinned barrel?

Anyway, as it turns out, the filing is proceeding superbly. Notch is VERY CAREFULLY widened very slightly, and is still square, metal surface is plenty smooth, and there is no harm if the bottom of the notch is lowered slightly in the process, since it is not used for sight alignment. This is a very simple and effective solution that will not even be noticeable to look at when finally sanded with #800 and blued. Will try this setting at the range and proceed further if warranted.

Someone once suggested bending the front sight slightly and I am glad I did not do that. It would have looked bent from then on, every time I looked at it. Would have bugged the **** out of me...

 

[riverrat38]

We don't need to guess at how far to move an adjustable sight to get the necessary correction. If you are off 1 inch at 25 feet, the ratio is 1:300. It is necessary to change the 25 foot range to inches, which is 300 inches. So, we need a correction of 1:300 in a distance equal to the sight radius. If the sight radius is 5 inches, divide 5 by 300 and get the correction of .017 inch, which is about 1/64 inch. It looks to me that if you are making the correction by widening the rear gap, you would need to remove twice that amount, as you only get half the correction in this case, when you recenter the front sight blade in the new gap.

rick

 

[tacotime]

I hadn't done the math because I was going to use actual shooting trials to get the correction... but I hadn't even thought that I need twice the mathmatical correction on the sight notch because the effect on target is only half of the widened amount! Good thinking.

The gun is showing 3.5 inches left at 25 yards. Not that bad for a 1-7/8 inch gun, but that same group can be on the target with a little work, and the plan is working so far. Testing over the weekend.

 

[tennexplorer]

Yes, you can turn in a pinned barrel. Especially the tiny amount you need. Remove the pin first. On most of the barrels, the channel cut for the pin is really big.

 

[Larry from Bend]

There's a special file with a smooth "bottom" that is used to widen sight channels. I've got one but can't bring the correct file name to mind. Brownell's has always sold them.

I've widened several sight channels --- In one severe case pf POA and POI being waaaaay different, I've built up one side of a front sight with JB Weld, also.

 

[tacotime]

The filing is going well... the Dremel with a cylinder diamond bit was used and a diamond flat file and regular carbon file. The Dremel requires a very steady hand.

The sight looks good. So far, enough has been removed to move the POI from 3.5in left to 2in left. Still more to go. It is hard to see the difference in the two sides of the notch. Barely noticeable on close look.

I also filed the top of the front blade and brought the POI up to even at 20 yards. Feeling good about this project so far...

 

[bronco45]

Check out Bowen Classic Arms and D&L Sports for an affordable rear sight fix.

 

[wrangler5]

I have a 442 that shoots way high and right - like 5 or more inches off center at 7 or so yards. (If I want to drop an 8" steel plate I basically have to aim at the edge at 7 o'clock.) Eventually I may send it back to S&W to see if they can do anything about it, but in the meantime the easiest way I've found to adjust the sights is with a Crimson Trace laser grip. Not much good at 50 yards or in bright daylight, but indoors, or outdoors on a cloudy day on a non-black target (I use IDPA practice targets, which are mostly white with gray scoring lines) it's a real hoot to see a hole appear where the red dot was.

Not as cheap as a file, of course.