PDA

View Full Version : Glock 20C sight height questions



jck397
11-09-13, 17:23
Need some help figuring out the proper sight height combo for my gun...

Back story: I just picked up a NIB Glock 20C. I had originally wanted Ameriglo Operators for it, but when an online vendor sent me a set of 2009 sights that I am in the process of returning and I needed the gun for a qual. this week, I went up a set of Trijicon HD sights from a local vendor since that was all that was available (Gl104Y for the large frame glocks; installed by a competent gunsmith). I shot the gun yesterday and it is printing low (about 1" low at 3 yds. to about 6" low at 15 yds.) I called Trijicon, and they told me that the sights might not be covered under warranty since they have been installed (???), and that I would have to send my slide in for them to inspect it to even see if they would make adjustments, and they may or may not charge me. The local vendor is either unable or unwilling to help me, and told me I should sell the sights online and buy a different brand. I don't want to be without my gun for that long, and I've decided to just take the loss and pick up the Ameriglos that I wanted in the first place and put the Triji's on the EE.

Should I just pick up the standard size G20 Operators, or should I start out with a shorter front/taller rear combo? And if so, combo do I want? Is it better to get a shorter front, or a taller rear? Does it make a difference that the Trijicons are taller than the Ameriglos would be? I put my info into Ameriglo's sight calculator, and it said I needed an offset of about .075", but I don't know:

1) If the difference in height between the Trijicons and Ameriglos makes a difference for the calculator
2) The height of the Trijicon HD front (I know the rear is 6.9mm or .271), so even if I was going to try to adjust, I wouldn't know which size Ameriglo front to work with.

Any help would be appreciated--I'd hoping to avoid having to go back for multiple sight installations and have to burn through a bunch of 10mm ammo chasing zero.

Thanks!

djegators
11-09-13, 21:02
Not sure I can help much at all, but I immediately have two questions:

1. What ammo are you using

2. Anyway you can compare the after market sites measurements to factory sights?

Like I said, I know this isn't much help, but I shoot my 20C with factory sights quite a bit and have no elevation issues.

jck397
11-09-13, 21:43
Not sure I can help much at all, but I immediately have two questions:

1. What ammo are you using

2. Anyway you can compare the after market sites measurements to factory sights?

Like I said, I know this isn't much help, but I shoot my 20C with factory sights quite a bit and have no elevation issues.

1) Remington UMC 180 gr. FMJ

2) Both the factory front and rear sights are shorter than the Trijicon HD sights. According to Ameriglo's website, the factory Glock front sight is .165, and I know the HD rear sight is 6.9mm. I don't know the Glock factory rear sight height, or the front sight height for the HDs.

I don't know if my 20 has different mechanical accuracy than others (I had a S&W M&P .40 that shot low--S&W sent me out a shorter front sight and the problem was solved) or if the HD sights are making a difference that factory-height sights would not.

REM_11
11-10-13, 04:55
The problem is most likely the gun, not the sights. I have the same(opposite) problem with a g4 19. Shoots 8" high at 25m. Have your gun smith put the stock sights back in place to verify. If you have the same issue, you can compare heights. It'll be easy to figure out a combo that will work.

Sent from my SCH-I535 using Tapatalk

jck397
11-17-13, 17:30
Thanks to everyone for their replies. I put the factory sights back on and shot groups today, and confirmed it's the gun Anywhere from 1.75" low at 3 yards to 6-7 inches low at 15. When I went to Ameriglo's sight calculator it told me I need to make somewhere around a .08" shift in my sight. Since I'm already using the shortest front sight (.165) and a .271 factory rear, this means I'd have to go up to around a .350-ish rear, and Ameriglo's only options are a .311 (too short), or .393 (a bit tall and suppressor height). Does this sound way off to anyone else? A suppressor rear with a factory-height front? Is this something I should contact Glock about?

vigilant2
11-17-13, 19:44
FWIW, I don't know how much this will help you as I don't remember(and can't seem to find my rear sight height, these are Warren Tacticals 2 -Dot tritium rears). I bought the set for my Glock 20C which upon installation was hitting low at 7yrds. I'm a decent shooter, but decided to have USPSA Grandmaster Shannon Smith shoot my gun to eliminate myself from the equation, it was hitting low for him at 7yrds also. I ended up going to Dawson Precision and having them make a custom .195 height front sight (tritium insert) for me. Problem solved. I used their on -site calculator and then ordered a custom front sight from them.

REM_11
11-17-13, 21:11
I too, went with Dawson's to correct the problem.

Sent from my SCH-I535 using Tapatalk

jck397
12-02-13, 15:58
After a less-than-helpful conversation with Glock (go online for instructions on how to send the gun back at your own expense) and not relishing the cost of custom sights for the life of the gun I called Bar-Sto--outstanding customer service! They said to send it in and they would check, at no cost, if it is something that can be fixed with a new barrel. Rather than spending almost $100 to overnight the gun to Glock to maybe get help, maybe not, this seems like a no-brainer. Updates to follow...