Where do your factory sights hit AND Off Center Primer Strikes... [Archive] - Glock Talk

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alank2
08-02-2012, 19:51
Hi,

Well guys, I went back to the range quickly tonight to see where I am shooting at 25 yards in terms of elevation.

I've had a total of 42 rounds on the G20SF before today and I added 8 more rounds. These are:

Winchester 10mm Brass (New), Hornady XTP 200gr (.400), Accurate No. 7 9.6gr, CCI Large Pistol (#300), 1.250 oal

The main issue - two rounds FAILED TO FIRE. I am not happy about this at all. Both rounds have a primer strike in them that looks plenty deep, but it is off center (between the center and the edge of the primer). I did do the recoil spring test when I got home where you pull the trigger back, aim the muzzle upwards, pull the slide back and slowly release it. It does not make it all the way up with the new factory spring. If I begin to turn it horizontal, it will lockup fully before being fully horizontal. Do you guys think this is an RSA issue or do I need to look at something else? I did not fire both rounds and can take a picture if you guys want to see them. Both rounds fit the barrel easily and have room to move and both rounds were checked in a case gauge ahead of time and still fit it now.

The second issue is the sights. The factory sights are shooting around 6.5" high at 25 yards. My load is running 1050 fps and I have a ballistic calculator that says the sights are 30 moa high compared to the bore. This is a zero at 1.5 yards and 170 yards! Does anyone else shoot so high at 25Y using factory sights?

If I adjust my ballistic calculator to balance the amount high and low I end up with a zero at 5 and 57 yards and for the first 67 yards it will be within +/- 1.25" POA. Running this through the site calculator at Ameriglo gives me a difference of 0.041" from what I have (which is too high). I need a shorter rear sight or taller front sight. I can drop the rear site to 0.256 from 0.272 and take care of 0.016" and raise the front site to 0.190" to handle the remaining 0.025". They don't have a 0.190" front so I'll have to decide between a 0.180" or 0.200". Has anyone done something similar? It seems like a lot of adjustment.

Thanks,

Alan

Any Cal.
08-02-2012, 21:30
I have/had the same site issue. Bought a 220 tall Novak front (Midway) and filed it down to where I liked it, then bought a Dawson FO front that was a similar height. Dawson will exchange fronts until they are right if you buy their Perfect Impact front AND rear.

Don't know about the off center hits. I did have a couple light strikes on my gun at first, but they quit after a couple hundred rds, and there were only a few of them. I assumed it was bad primers because they were old, but it has been a non-issue since then.

Mik
08-04-2012, 22:30
In my experience, off center primer hits have been a sign that the slide is not going fully into battery.

Yondering
08-05-2012, 13:02
The second issue is the sights. The factory sights are shooting around 6.5" high at 25 yards. My load is running 1050 fps and I have a ballistic calculator that says the sights are 30 moa high compared to the bore. This is a zero at 1.5 yards and 170 yards!


You didn't say, is this a stock OEM barrel? If it is, send that gun back to Glock. It's shooting high because the rear of the barrel is too low in the slide. Glock needs to fix that, don't try to band-aid it with different sights.

I'd say get a stiffer recoil spring too, but get the barrel lockup issue taken care of first.

alank2
08-05-2012, 13:15
Hi,

In my experience, off center primer hits have been a sign that the slide is not going fully into battery.

I agree, measuring the center of the strike to the center of the primer, it is about 0.035" difference so I'm guessing that is the amount the rear of the barrel wasn't lockup fully at.

You didn't say, is this a stock OEM barrel? If it is, send that gun back to Glock. It's shooting high because the rear of the barrel is too low in the slide. Glock needs to fix that, don't try to band-aid it with different sights.

Yes, OEM stock barrel with stock sights. I'll give them a call...

Thanks,

Alan

Any Cal.
08-05-2012, 13:36
Yondering may be right, but mine did the same thing w/ an aftermarket barrel as well. When I called Glock, they told me I could buy different rear sights to fix the problem. If they tell you something different, I would be interested to hear it as well.

Yondering
08-05-2012, 18:13
Off center firing pin strikes in a stock barrel indicate something is wrong with the lockup; Glock needs to fix it.

emtjr928
08-05-2012, 18:25
If rsa won't pass battery test get it back to glock, as something is amiss.

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Any Cal.
08-05-2012, 18:46
Off center firing pin strikes in a stock barrel indicate something is wrong with the lockup; Glock needs to fix it.
How far off center is an issue? I know mine is a bit off, but not by a 1/3 or something. I am thinking mine is fine, but shot really high, but your posts are making me question that stance. I know that the sights are the same for my factory and AM barrel in my case.

Yondering
08-05-2012, 20:26
How far off center is an issue? I know mine is a bit off, but not by a 1/3 or something. I am thinking mine is fine, but shot really high, but your posts are making me question that stance. I know that the sights are the same for my factory and AM barrel in my case.

Got a picture?

If your factory and AM barrels both do the same thing, something's wrong with the slide or frame. Could be as simple as the locking block, or something a lot more complicated. Could be just a burr on the slide at the front of the barrel hood, but that should go away if you've shot it a lot.

I'm assuming the firing pin strike is off center vertically, not sideways?

Any Cal.
08-05-2012, 22:33
I could get a pic, it is just a bit to the left, but OK vertically.

Yondering
08-06-2012, 00:12
Weird, that's unusual. Is the firing pin hole off-center in the slide?

dm1906
08-06-2012, 00:16
Yeah, unusual. If it's off-center enough to notice by looking, something's wrong that needs to be fixed. Bad slide.

Any Cal.
08-06-2012, 01:04
Here is some brass, tell me what you think.

http://img267.imageshack.us/img267/3953/img0811dn.jpg

I also just noticed that the cartridges point a bit to the left of the center of the barrel, and feed to the left. The gun was really dirty, but I just had a few FTF due to the nose hitting the left side of the barrel slightly. It hadn't happened before, I am hoping it is just because the gun was dirty, there was a lot of gunk built up just below the extractor. Here is another pic. Even clean cartridges point slightly left of center, but I haven't had the issue after 2-300rds of these bullets, but then it happened once, and another day shortly after twice in a 50rd box. Two different mags appear to do the same thing.
http://img820.imageshack.us/img820/4307/img0809bg.jpg

This is showing the LW barrel, not the factory one.

dm1906
08-06-2012, 01:36
Here is some brass, tell me what you think.



I also just noticed that the cartridges point a bit to the left of the center of the barrel, and feed to the left. The gun was really dirty, but I just had a few FTF due to the nose hitting the left side of the barrel slightly. It hadn't happened before, I am hoping it is just because the gun was dirty, there was a lot of gunk built up just below the extractor. Here is another pic. Even clean cartridges point slightly left of center, but I haven't had the issue after 2-300rds of these bullets, but then it happened once, and another day shortly after twice in a 50rd box. Two different mags appear to do the same thing.


This is showing the LW barrel, not the factory one.

Some hits center, some not. May be a sloppy firing pin channel, or worse. I'd be more concerned with the variation than the actual pin hit location. Not all pin hits are center, but they all should be consistent. I'd get it fixed.

texas 48
08-06-2012, 18:07
Detail strip and clean fp channel. Gunk or bits of primer caused intermittent ftf.

Sent from my EVO using Tapatalk 2

nickE10mm
08-06-2012, 20:53
All 15 or so Glocks with stock sights I've owned in my life have shot poa with in inch or so at 25y. As for the off center hits, I'd be concerned about your barrel / lock-up and firing pin channel. I actually had a Glock with a buggered up firing pin channel sleeve (from factory). Once I replaced it, light strikes were eliminated. Also, remember: NO OIL / LUBE in te FPA CHANNEL AREA for Glocks!

alank2
08-06-2012, 21:02
Hi,

I'm not sure about Any Cal's, but my striker channel is clean. I always detail strip new slides from Glock and remove the oil they put in there. The 6.5" off @ 25Y does bug me even though the top of the barrel hood seems very flush with the top of the slide. I am also not happy about how sloppy the chamber is - If I remove the barrel and put a round in it, it has twice the free movement in the chamber that my G19 has... I'm going to press Glock to send a pickup tag for it and see if I can get them to replace the barrel with one that has a tighter chamber. Perhaps that will change the POI too...

Thanks,

Alan

ctious
08-06-2012, 21:34
My g 20 shoots way high with both my stock slide and lone wolf long slide. The stock sights suck. I was 5in high at 25 yards. Got some advantage tatical sights and fixed it.

Just dump the stock sights. As the primer strike. Check your channel liner. Is there one in it? LOL.

alank2
08-09-2012, 16:31
Hi,

Well, my G20SF is on its way back to Glock. I put in a note politely requesting they take the dummy round I included and find me a barrel with a tighter chamber. Hopefully they will address the 6.5" high @ 25Y and lockup issue at the same time. I guess we'll see what they send back.

Thanks,

Alan

blastfact
08-09-2012, 21:17
Well I don't think much of your calc's.

Why the pic of .40 useless S&W brass?

alank2
08-09-2012, 21:22
Hi,

Well I don't think much of your calc's.

What exactly are you questioning?

Why the pic of .40 useless S&W brass?

I am guessing that Any Cal was posting a picture of brass shot through a conversion barrel...

Thanks,

Alan

alank2
08-18-2012, 12:19
Hi,

Glock called me about it and they replaced the rear sight with a lower one to lower the POI at 25Y. I probably will still need a taller front sight too, but I'll test that. The technician said he tried the dummy round I supplied in a few replacement barrels and all were the same level of looseness in the chamber, so I'm getting back the same factory barrel. I went ahead and ordered a black storm lake factory length barrel so with any luck that will fix all my issues. I also ordered a Sta-Tite rod with a 20# ISMI spring on it from btguiderods to test out as well.

Thanks,

Alan

Yondering
08-18-2012, 15:04
Hi,

Glock called me about it and they replaced the rear sight with a lower one to lower the POI at 25Y.

What did they say about the off-center firing pin strikes? That was the biggest indicator of something wrong, from your description. I'd want that addressed.

alank2
08-18-2012, 15:07
Hi,

What did they say about the off-center firing pin strikes? That was the biggest indicator of something wrong, from your description. I'd want that addressed.

They said they could not reproduce the issue. He said he shot a couple magazines of blazer aluminum and did not experience it. I'm going to switch to a storm lake barrel and use a Sta-Tite recoil rod from btguiderods with a 20# ISMI spring on it. Once I get all that in; I'll do some more testing and see what happens.

Thanks,

Alan

alank2
08-21-2012, 18:33
Hi,

Pistol arrived today with two pretty nice looking test targets:

I measured from the outer edge of the groups, including where the paper was affected by the shot, but still present.

0.894" 7Y hand held 5 shots all touching, 4 leaf clover!
2.031" 25Y rested 6 shots

I tried the BTguiderod Sta-Tite rod in it and I have to say that it is very nice. Very smooth and no more screechy noise when the slide is actuated like the factory RSA.

I may go ahead and wait for the Storm Lake barrel before tinkering with it more to not waste brass...

Thanks,

Alan