Input on replacing a rear sight with pusher tool?

[Ralph III]

Hello All,
I would like to replace a rear Trijicon night sight with a stock Kahr sight on my S9 and would like some input.

Just FYI: I purchased the S9 brand new a few months ago and it mistakenly arrived with i-dot sights. The sights were spot on accurate, btw. Soon afterward I decided to replace the front sight with a Trijicon night sight from Kahr. The gun however was then shooting high. Consequently, I decided to have Kahr install a matching rear Trijicon night sight thinking that would put it back on target but it didn't work. The gun is shooting 1in high for every 10ft. So at 10ft it is 1in high. At 50ft it is 5in high. These results are conclusive from several range trips and not acceptable.

I really do not want to send my gun back into Kahr to change out the rear sight as they will now charge me and it may take several weeks. Anyhow, I purchased a sight pusher tool as seen HERE. Is there any insight you can confer upon me in doing the job?

*I plan to lubricate the rear sight prior to removing it.
*The dovetail notch appears to be tapered. So it will be removed from left to right and then installed from right to left. I've seen this mentioned by others also.
*I will sight it in prior to applying locktite.

What else do I need to consider or look for? Do note, this tool doesn't have a pusher tooth. It simply pushes from the mid to upper part of the sight. The rear Trijicon night sight will be offered for sale if anyone is interested.

God Bless,
Ralph

[finpro]

Have you examined your sight picture? Some will shoot higher. I prefer a sight picture that puts the POI at the top center of the front sight when aligned with the rear top. I prefer to cover less of the target. You might try aligning using your current sight picture on a target at a known distance, preferably from a rest, and seeing if another picture would put your shots nearer to where you want them. You might also try different types and weights of ammo. Do other shooters of your S9 have the same results? If you have not done so, try shooting from a rest with a very tight grip to diminish some factors that may influence this.

You might check your existing rear sight with your incoming rear. To lower your POI by 5" at 50', you need a rear lower by 1/120 of your S9 sight radius. Measure from rear of the front sight to the rear of the rear. By my math, using an old P9, you need to lower the rear by about 0.042". If the incoming rear is not that much shorter, I suggest going to dawsonprecision.com and seeing if you can get a shorter rear or a taller front by the amount you calculate. I think they will answer questions and they have a good reputation.

If you go forward with sight replacement, I recommed using "sharpening oil", also called "honing oil", which penetrates well and cleans up well. Use masking take on anything in harms way. Work on the slide removed from the pistol. Place the moving piece on the pusher as low as possible on the sight. When installing the incoming sight, try to insert it into the dovetail by hand. If it will not go in halfway with limited force, polish the left corners of the sight and remove a slight amount of metal from the bottom of the sight. A good way to do this is to use a very fine grit sandpaper on a very flat surface. I would use a sheet of 1000 grit or higher sandpaper on a glass top table moving the sight with light pressure sideways as it would fit into the dovetai. Go slowly and stop and retry the fit into the dovetail. When it will fit halfway in with hand pushing go to the sight pusher.

When installed, remove the lubricant. Alcohol or dish detergent is good for this. Unless Loctite is necessary, you might try to avoid using it. If you decide to use it, use a lighter grade and place it in the dovetail at the sides of the sight, not beneath the sight. I have never had a problem doing it this way.

Good luck.

[Scarywoody]

You'll be surprised how easy it will be. Just go slow and make sure everything is straight. Avoid scrapes.

[Ralph III]

Thanks for the replies.

I did perform the sight replacement and it went very smoothly. Here is the process I used.

1. Soaked the rear sight in penetrating oil for about 1 hr.

2. Installed it in the sight pusher and pushed from left to right (dovetail is tapered). It took a little bit of torquing but finally the sight popped (released) and then pushed right out.

3. I then tried reinstalling the old sight to see how far I could insert it via hand. I was able to insert it about 1/4 of the way which is how far I could insert the new sight as well. So I didn't feel the need to take any metal off of the new sight by sanding on it.

4. Upon inserting the new sight via hand, I wrapped it in painters tape, and then tapped it on a wooden 4 x 4 post until it was flush with the slide. This allowed me to drive the new sight in with no chance of causing any sort of damage (metal > wood). This really was butter and better than tapping it with a hammer or punch, IMHO.

5. I then reinserted it into the pusher and finished pushing the sight into place (right to left)

All in all, it was much easier than expected.

God Bless,
Ralph

[gb6491]

Thanks for the update Ralph!

[Ralph III]

Thanks for the update Ralph!

You're welcome. Hope it helps someone else.

Ralph