Author Topic: G20 rear sight not centered.  (Read 609 times)


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G20 rear sight not centered.
« on: February 22, 2017, 11:04:02 PM »
what i own is a G20.SF. Never shot before i bought, brandnew in case, mag, etc. whole 9
Ive had some trouble making decent shots with it.
My eyes are not great anymore at 44 yrs old, so i took the slide off and asked my wife, daughter and son to look at rear sight.  They all said, its to the left a hair (insert political joke)
so do i tap it with a punch. Im not a Gsmith.


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Re: G20 rear sight not centered.
« Reply #1 on: February 23, 2017, 05:36:33 AM »
there is a tool to adjust, sort of like a c-clamp
They run from $10 to $100 depending on the quality and fancy features


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Re: G20 rear sight not centered.
« Reply #2 on: February 23, 2017, 05:46:24 AM »
You said you are not making decent shots... Are your groups shooting to the left?

My Glock 20sf came with polymer sights.  I personally would not attempt to tap them with a metal punch, hard to control how far they can go in the dovetail and you do run a big risk of damaging your sights and/or the finish on your slide.

What I did was I shot my gun as it was, from a supported rest (rolled up shirt on my range bag).   I made a 5 shot group.   Wrote the range distance on the target and took it to my local gun store.  In my case it was also my local gun range.   They did some quick math to determine how far the rear sight needed to be moved - based on the grouping relative to the bullseye and the distance shot.   They put a Glock sight adjustment tool on the slide and moved the rear sight exactly the correct distance to shift my groups to the bullseye.   The tool gently pushes the rear sight in the dovetail without damaging it.   It also allows very precise adjustments of the sight.  Usually the charge for this is free or around $10.   

That being said I don't know if you are able to do this or not.   If not then you will want to use a padded vice to hold your slide stable.   Use a Delrin or hard polymer punch.   They are made not to mar the finish on your slide and should cut down on the chance of damaging your sights.   Gentle taps.  I believe you can find the punches at MidwayUSA, Brownells and etc.

You can also buy the tool to do it yourself.   But unless you own lots of Glocks that need adjusting, it is going to be used once and never again.

Good luck and enjoy your SF!


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Re: G20 rear sight not centered.
« Reply #3 on: February 23, 2017, 06:29:21 AM »
As mentioned, you need to shoot a group or two at a known distance, from a rest and determine how far off the sights are.  From that information you can determine how much to move your sight.  Here is a sight adjustment calculator:

And a cheap glock adjustment tool:

This is about the cheapest tool I have seen.  Or, find a local shop and see if they will adjust it for you.  Or delron punches. 


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Re: G20 rear sight not centered.
« Reply #4 on: May 25, 2017, 11:19:26 AM »
Over the yrs I've owned 2 block gen2 17's , 2 late gen 3 19's and now a gen4 g20 . Knock on wood the sights have been on from the factory . I would try the suggestion from the previous poster would try it 1st and I deally from a rest if possible . If this is you 1st block be aware many 1st time users do pull the shots to the left from my experience. 


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Re: G20 rear sight not centered.
« Reply #5 on: May 25, 2017, 11:32:33 AM »
I would not hit the plastic sight to try and move it. If it's your first Glock it's not uncommon to see shots pushed left if you're a righty.

I about broke a Glock brand sight tool trying to change sights on a 42. Sometimes the sights on a Glock can be stubborn and jump all at once. If I had tried tapping that particular set, I would have busted the sight before it moved.

While working at my friends shop I did a lot of trading. Ive had a 17L, several 23's, a 26, three 27's, a 32, a 33, 39, Gen4 19, three Gen 3 G30's and now my 29. I've probably missed a few too  :o
« Last Edit: May 25, 2017, 11:42:50 AM by Overkill338 »
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