Question about dialling in my Glock 17?

[nternal]

I recently got a Glock 17 equipped with trijicon night sights. The sights were supposedly factory installed but I have my doubts because the front sight came loose and fell off after a few hundred rounds of shooting. I had the store where I bought it reinstall the front sight with a bit of lock tight to ensure this didn't happen again. The gun is squared away now and, after another 2000 rounds, I find that it shoots a little bit high. I had an expert marksman check it out and he concurred. I find that I have to line up the front sight about 1mm lower than where it should be to be properly centered with the rear sights. I have 3 questions about this issue:
1) Is there a spacer used with the trijicon front sight that I may have lost when it fell off?
2) Would it be possible to place a small shim under the front sight to lift it that tiny bit it would take to get it dialled in perfectly?
3) If there is no way to modify the trijicon sights can anyone recommend a high quality adjustable night sight?

[SamuelBLong]

I recently got a Glock 17 equipped with trijicon night sights. The sights were supposedly factory installed but I have my doubts because the front sight came loose and fell off after a few hundred rounds of shooting. I had the store where I bought it reinstall the front sight with a bit of lock tight to ensure this didn't happen again. The gun is squared away now and, after another 2000 rounds, I find that it shoots a little bit high. I had an expert marksman check it out and he concurred. I find that I have to line up the front sight about 1mm lower than where it should be to be properly centered with the rear sights. I have 3 questions about this issue:
1) Is there a spacer used with the trijicon front sight that I may have lost when it fell off?
2) Would it be possible to place a small shim under the front sight to lift it that tiny bit it would take to get it dialled in perfectly?
3) If there is no way to modify the trijicon sights can anyone recommend a high quality adjustable night sight?

1) No
2) Possible, but not recommended at all.
3) The rear can be lowered - again... not recommended; Dawson Precision makes a rear adjustable tritium.

but before you go swapping rear sights or modifying the trijicons...

1) how far off is "a little bit high"?
2) what distance are you shooting at to establish zero?
3) what hold are you using - drive the dot or 6 o'clock?
4) have you shot multiple types of ammo and bullet weights?
5) were your groups and your expert's off by the same amount of deviation?

[JHC]

Great list of followup questions by Sam. A little more info would be ideal.

Several of our Gen 4 Glocks shoot quite high (POI 8" above POA) at 25 yards FWIW. Taller front has remedied that.

[JV_]

(POI 8" above POA) at 25 yardsI would send that gun back, that requires a sight adjustment of almost .050"!

[JHC]

I would send that gun back, that requires a sight adjustment of almost .050"!

That's not unheard of with Gen 4s. Crazy eh? .250 tall has gotten then such that a 6:00 hold on a 4x6 will put rounds on the card. And since 6:00 hold is my lifelong habit . . .

[nternal]

but before you go swapping rear sights or modifying the trijicons...

1) how far off is "a little bit high"?
2) what distance are you shooting at to establish zero?
3) what hold are you using - drive the dot or 6 o'clock?
4) have you shot multiple types of ammo and bullet weights?
5) were your groups and your expert's off by the same amount of deviation?

1,2) To put rounds on a 4x6" metal target at 20 meters I need to place the top of the front site about 1mm below the line made across the top of rear site (I employ a POA sight picture). I'm not an experienced enough shooter to fully understand the mechnanism but I seem to need to line up the rear sites a tiny bit above the front sites at anything from 7-10 meters. I know that doesn't really make sense but since I'm shooting 4X6" metal targets I'm probably making miniscule unconcious adjustments at these different distances.
3) I'm using POA (Target is obscured by my front sight. I guess this is called "driving the dot")
4) I haven't taken bullet weight into account and was shooting 124 gr standard pressure.
5) If I remember correctly the "expert" who checked it (Slavex) was shooting about 1/2"-1" high at 5 meters.

Ps. It was coincidental that this slight discrepency was pointed out by my coach just before I started shooting metal targets that could give me immediate feedback on how my sight picture and trigger control were effecting my accuracy.

[nternal]

Based on all the variables of bullet weight, target distance and sight picture employed I probably need adjustable sights to fine tune my gun to my own exact requirements. Am I going to be creating a whole new set of problems (such as establishing a baseline from which to work) with something a like Meprolight Tru Glow adjustable sights?

[JBP55]

Based on all the variables of bullet weight, target distance and sight picture employed I probably need adjustable sights to fine my gun to my own exact requirements. Am I going to be creating a whole new set of problems (such as establishing a baseline from witch to work) with something a like Meprolight Tru Glow adjustable sights?

You may not have the correct sights for your pistol. The height of the front sight should be .165 and the rear should be .256 for a G17.

[nternal]

You may not have the correct sights for your pistol. The height of the front sight should be .165 and the rear should be .256 for a G17.

I doubt they are the wrong ones since they were supposedly factory installed by Glock and the store I bought the gun from is one of the most reputable gun shops in Vancouver. I also don't have a micrometer with which to measure them.

[SamuelBLong]

If you were lined up on a paper target at 20m... The tip of your front sight was level with the top of the rear, and the dot superimposed over the center of the target, how far off would the bullet impact be from the center of the target? Is it impacting at the tip of the front sight or is it higher than that? In order to figure out exactly how many thousandths of an inch off your sights are, we really need to know deviation based on a perfect sight picture (equal height w/ equal amounts of light on either side of the front sight).


I doubt they are the wrong ones since they were supposedly factory installed by Glock and the store I bought the gun from is one of the most reputable gun shops in Vancouver. I also don't have a micrometer with which to measure them.

You might want to make sure that they didn't accidentally install the G20 / G21 sights on that gun. It would be very helpful if we had actual measurements. Surely someone you know reloads and has calipers that you could borrow.

It wouldn't be the first time someone had that exact problem with a 9mm gun. My G26 arrived with G21 sights on it.


Based on all the variables of bullet weight, target distance and sight picture employed I probably need adjustable sights to fine tune my gun to my own exact requirements. Am I going to be creating a whole new set of problems (such as establishing a baseline from which to work) with something a like Meprolight Tru Glow adjustable sights?

As for stepping in a new mess if you get adjustable sights... If you're going to install adjustable sights, get the full set (matched front and rear), and you shouldn't have any issues. Center up the rear adjustments both in windage and elevation and shoot for record. There should be enough adjustment to get the gun zeroed as you want it to be.

You're just going to have to put in the time to shoot very accurately at the intended zero distance, so that you can precisely and accurately dial in the sights.

[nternal]

You might want to make sure that they didn't accidentally install the G20 / G21 sights on that gun. It would be very helpful if we had actual measurements. Surely someone you know reloads and has calipers that you could borrow.

It wouldn't be the first time someone had that exact problem with a 9mm gun. My G26 arrived with G21 sights on it.



I guess I'm just going to have to bite the bullet and get the gun checked out. :o Thanx for sharing your experience and knowledge on this.

[nternal]

You may not have the correct sights for your pistol. The height of the front sight should be .165 and the rear should be .256 for a G17.

I just took the gun to the back to the store and got the Trijicon sights measured. The measurements were lower for both the front and back. Does anyone know if the numbers quoted by JBP55 are accurate for trijicon sights? Also the front sight had loosened again. What's up with that? I thought trijicon was the gold standard for night sights. This is really starting to piss me off since I confirmed that the gun was ordered from Glock with these sights. Does everyone go through this kind of garbage to get a Glock dialled in properly?

[JHC]

I just took the gun to the back to the store and got the Trijicon sights measured. The measurements were lower for both the front and back. Does anyone know if the numbers quoted by JBP55 are accurate for trijicon sights? Also the front sight had loosened again. What's up with that? I thought trijicon was the gold standard for night sights. This is really starting to piss me off since I confirmed that the gun was ordered from Glock with these sights. Does everyone go through this kind of garbage to get a Glock dialled in properly?

Generally not when the correct sights for the gun are installed. An earlier poster indicated the G21 sights are shorter. You just reported the sights measured lower.

I would take JBP55's word for it based on his heavy Glock experience (for an agency as well as personally) that vastly exceeds my own.

Doesn't sound like Trijicon's mistake to me. They don't install the sights.

[nternal]

Generally not when the correct sights for the gun are installed. An earlier poster indicated the G21 sights are shorter. You just reported the sights measured lower.

I would take JBP55's word for it based on his heavy Glock experience (for an agency as well as personally) that vastly exceeds my own.

Doesn't sound like Trijicon's mistake to me. They don't install the sights.

I didn't say this was a Trijicon mistake. I said the sights were factory preinstalled on the new gun (by Glock). I have sent an email to Trijicon so that I can get the specs directly from them. I'll also contact Glock to find out how this can be checked and rectified i.e. the fellow at the gun shop who measured them for me wasn't even sure whether the rear sight should be measured at the front or the back (it has a bit of a taper on top).

Ps. When I asked if others have had to go through this song and dance I was referring to the fact that the front sight has loosened twice. I don't know if this is a common problem or whether it might be because they are the wrong sites. I would be VERY surprised if the mounting platform for the iron sites varied depending on the model of Glock. Companies generally try and minimize unnecessary machining variations.

[DocGKR]

nternal:

1. There are reasons why so many folks routinely throw away their factory Glock sights...

2. Always strive for a perfect sight picture (front and rear sights at equal height w/equal amounts of light on either side of the front sight) with your handgun. If you need to alter where the bullets impact on the target--DO NOT change your perfect sight picture, instead simply take that perfect sight picture and hold it higher/lower/right/left on the target...

[JHC]

I didn't say this was a Trijicon mistake. I said the sights were factory preinstalled on the new gun (by Glock). I have sent an email to Trijicon so that I can get the specs directly from them. I'll also contact Glock to find out how this can be checked and rectified i.e. the fellow at the gun shop who measured them for me wasn't even sure whether the rear sight should be measured at the front or the back (it has a bit of a taper on top).

Ps. When I asked if others have had to go through this song and dance I was referring to the fact that the front sight has loosened twice. I don't know if this is a common problem or whether it might be because they are the wrong sites. I would be VERY surprised if the mounting platform for the iron sites varied depending on the model of Glock. Companies generally try and minimize unnecessary machining variations.

If I misunderstood or jumped to a conclusion, my apologies. But loosening as well is probably an installation issue, not a sight manufacturer shortfall.

I've only gone through this when I didn't take care installing my sights. In this case, some 3rd party individual is involved.

[JBP55]

I just took the gun to the back to the store and got the Trijicon sights measured. The measurements were lower for both the front and back. Does anyone know if the numbers quoted by JBP55 are accurate for trijicon sights? Also the front sight had loosened again. What's up with that? I thought trijicon was the gold standard for night sights. This is really starting to piss me off since I confirmed that the gun was ordered from Glock with these sights. Does everyone go through this kind of garbage to get a Glock dialled in properly?



Regardless of brand the rear sight should be approximately .010 taller than the front sight on a small frame Glock when measured from the top of the slide to the top of the sight. The front sight height is the same on small frame Glocks as well as large frame Glocks but the rear sight is approximately .016 taller on a large frame Glock.