I’m testing a set of Trijicon HD Night Sights on a Gen 3 G17. It’s easy to shoot good groups with them, but POI issues are driving me nuts.
At 10 yards, POI is 2.375" over POA.
At 25 yards, POI is 6.25" over POA.
At 50 yards, POI is 12.5" over POA.
Basically, my zero is somewhere between 150 and 200 yards. Aside from the color difference, Trijicon makes two versions of these sights, the GL101 and GL104. I’m thinking I may have ended up with a GL104 set when I needed a GL101 set.
Does anyone know what the difference is between them?
In order to get POA to equal POI at 25 yds for my three G19s and two G34s with my carry ammo, Fed 147 grain HST std pressure (P9HST2), I had to go with a taller than stock front sight. They all shot about 2-3" high at 25 yd in my hands with the stock sight heights. Based on my experience it appears to me that POA/POI mismatches with 9mm Glocks (at least with 147 gr ammo)aren’t unusual.
This is a significant reason I am using Ameriglos exclusively on my Glocks now. They offer a variety of sight heights.
I’ll be happy to post a picture of them when I get home from work this evening.
I want these sights to work. I really like them–they’re easy to see, fast on target, and I shoot good groups with them. Also, the difference in POI between using the ball and the top of the front sight for POA is small–0.75" at 10 yards, and 2.5" at 25 yards.
It certainly does sound like you got the 104’s intended for the 20/21 series of Glocks. If my memory serves correct the rears on the 20/21 series are a bit taller than the 9mm. Would explain why you’re shooting high all the time.
I swapped emails with one of their customer service folks today. He’s been helpful, and pointed out that since I never shot the gun with the stock sights, we have no baseline and the gun may be at fault. I doubt it’s ammo–records of tests with a different G17 show that load I used hits squarely in the middle of where a dozen or so other loads hit.
The Trijicon CS guy also mentioned that the GL101 front sight is .215" tall, while the GL104 front sight is only 0.200" tall. A difference of 0.015" doesn’t account for the POI discrepancy I’m seeing, so it seems doubtful that I got the wrong set of sights.
I ordered an Ameriglo front blade last night. I’ll re-install the factory plastic sights and shoot a few groups with them this weekend. Then we’ll have another piece of the puzzle.
Remove the HD sights and reinstall the OEMs. Shoot and see where you’re at. I have heard of POI deviation in the 9mms with the HD sights, but not to the extent you are experiencing.
This G17 hits in exatly the same place with the factory sights as it did with the HDs, so it’s not the sights. I’d kinda like to hang on to this one–it’s relatively accurate and I’ve put 1,500 rounds through it with no issues, including 650 in a class.
There’s a real temptation to just stick a taller front sight on there and call it good, but I see a certain logic in sending it back to Glock.
I’m confused by the “relatively accurate” comment…it’s not accurate relative to anything. You can get a police trade-in for $400 that’s going to shoot better.
Almost every Glock is going to shoot better than 6" high at 25 yards. That’s not acceptable, and you should send it back.
I recently bought a Gen2 G19 for $400 bucks. It was an LEO trade-in. I replaced the slide lock, slide release lever, recoil spring, and sights. It shoots as well or better than any other Glock I bought brand new.
If you’re buying one that was built 3+ years ago, you should expect the standard of performance that they’ve spent the last few years destroying. The sights you bought are expensive; put them on something that works the way it was intended to work.
How do you shoot with other guns? Have you ever run any accuracy based tests such as “The Humbler, 700 point aggregate” ?
How large are your groups?
In what class did you shoot 650 rounds through this gun and not notice the huge POA/POI diff ?
I dont know you, so dont take it personally, but it may be you and not the gun. Those are our choices. Either something is really wrong with the gun or you are tossing shots high (normally “heeling the gun”).
I can shoot 1.5” groups offhand at 25 yards with a Smith K22. My groups get bigger caliber goes up and barrels get shorter.
I doubt that the Humbler is relevant, as it tests speed and accuracy with both hands, and with each hand individually. POI is the issue here.
This gun shoots into 3-3.5” at 25 yards with good hollowpoint ammo; groups with training ammo are slightly larger.
I knew before the class that I had this POI issue. I also knew that the class would not require shooting beyond 10m, so I went ahead with it. At that point, I still thought it was the sights.
I talked to the folks at Glock this morning, and I’m sending the gun back to them this week. I’ll keep you posted.
I know this is a bit of a necropost, so I apologize.
Did this ever get resolved for you? The reason I ask is because I’m experiencing the same issue with the same setup (Gen 3 G17 with Trijicon HD sights installed). I’m wondering if I should send it back to Glock or look at putting a taller front sight on it.
Glock Customer Service failed miserably on this. I sent the pistol back to them with a detailed letter and asked that it be tested at 25 and 50 yards. They returned it a few weeks later with a target that had one three-shot group (about 1.5") been fired at 15 yards and no other explanation. I called trying to learn more about what they had done, but I was only able to talk with slack-jawed yokels who were utterly uninterested in helping me. I gave up on Smyrna after that. I fully expect to have this problem again, and since the shipping on this little escapade cost as much as a new set of sights, I’ll start with new sights and waste no further time with the factory.
The folks at Trijicon didn’t have much help to offer, but to be fair, it wasn’t really their problem and the HD sights had just come out so they were busy selling them as fast as they could build them. I hear on the interwebs that they make a taller HD front sight, but that they’re expensive and the lead time is pretty long. That’s all I know about them, so you should contact them to verify that. (I REALLY like HD sights. I’ve used them on other Glocks, and they’re easily my first choice for a carry pistol—if the pistol is properly set up from the factory.)
After the pistol came back from Glock, it took another few months of dicking around with Brownells, Ameriglo, UPS, etc. to get things sorted out. I finally went to an Ameriglo .320” (I think) front and a Meprolight adjustable rear. I added a Wilson barrel a while later, and I now use this pistol for everything—IDPA, EDC, etc. I used it to shoot the 100-yard groups that I posted (https://www.m4carbine.net/showthread.php?144226-The-G17-at-100-Yards), and if the planets align in October, I’ll shoot a blacktail deer with it.
Grantc4I has commented on the Glocks-hitting-high issue in other current posts around here. I lack the background to agree or disagree with him, but I listen when he talks.
Adjustable sights corrected things for me, but I feel like that is a workaround and not the proper fix.
I put the sights on before I swapped barrels, so they did correct the POI issue. There was a slight POI shift after I fitted the Wilson barrel, but I’d expect that even if I had replaced the factory barrel with another factory barrel. I couldn’t find in my notes where I tested for that difference, but I did have to rezero to shoot an IDPA match.
That said, I also had TigerSwan upgrade a different G17 to their “Instructor Glock 17” package http://proshop.tigerswan.com/tigerswan-custom-glock-17.aspx Once it arrived, I tested it with both the Wilson barrel and the factory barrel for groups and POI at 50 yards. I fired a 10-shot string, then switched barrels, then repeated this twice more for each barrel. The POI for both groups differed by about 3.25" at 50 yards, or not that much.
I’d stick with changing the sights as the more effective way to alter POI, at least with my level of expertise in fitting barrels. A more talented pistolsmith might have a different answer.
