Off-Center Primer Strikes on a Brand New Glock 20 3rd Gen.

[I922sParkCir]

Good Morning! I just picked up a brand new Glock 20 3rd Gen, replaced the sights with Dawson adjustable FO's (https://dawsonprecision.com/copy-of-dawson-precision-glock-adjustable-sight-set-black-rear-black-front/) installed a Vicker's mag catch (https://tangodown.com/shop/vickers-tactical-extended-glock-mag-release-4510mm/), loaded up 150 rounds of 10mm, and headed to the range. No changes were made to the trigger, or action.

I was impressed with how well I was able to shoot the gun. I'm not a great shooter, and while this wouldn't be impressive to those who are, I could easily make 2.5"-4" groups at 50 feet standing. That's about as good I can shoot any handgun. Unfortunately, with the Dawson's adjusted their lowest I was consistently shooting 2" high. Time to put Dawson's "Perfect Impact Promise" (https://dawsonprecision.com/why-buy-dawson-perfect-impact-sights/) to the test.

46593

The only real issue is I've had is for 2 rounds that my friend shot he reports that the gun may not have been completely in battery and failed to fire. We checked the primer strikes and they were off center. I guess it's good that the primer didn't ignite if it was in fact out of battery.

46592

I've heard that the Glock 20 is a bit undersprung for proper 10mm loads, so I imagine that a stronger recoil spring may be in order. The gun passes the RSA test, but I've already ordered a ISMI stainless steel guiderod with an ISMI 20 and 22 pound springs just in case.

Any other ideas of what it could be? Anything I should check?

Notes:
- My friend, an experienced shooter, has been informed not to press the trigger if he ever sees a gun slightly out of battery. He should have known better.
- Ejection was all over the place. Sometimes 2 o'clock, sometimes straight up, sometimes to the right, and sometimes to my face. This could totally be my grip and follow through.
- This is the load data:
* Bullet: 180gr Precision Delta FMJ Flat Nose
* Powder: 12.5 gr Accurate #9
* Federal Large Pistol Primers
* New Starline
* OAL: 1.25-1.26"

* Bullet: 180gr Precision Delta FMJ Flat Nose
* Powder: 12.7 gr Accurate #9
* Federal Large Pistol Primers
* New Starline
* OAL: 1.25-1.26"

* Bullet: 180gr Precision Delta FMJ Flat Nose
* Powder: 8.4 gr Power Pistol
* Federal Large Pistol Primers
* New Starline
* OAL: 1.25-1.26"

* Bullet: 180gr Precision Delta FMJ Flat Nose
* Powder: 8.8 gr Power Pistol
* Federal Large Pistol Primers
* New Starline
* OAL: 1.25-1.26"

[jl1288]

Howdy,
Those primer hits don't look like what a factory glock striker looks like to me. Second, yup they are definitely under sprung. Same with the 40 S&W. I went with the ISMI 24lb spring in my G20. My G23 is using a 22lb ISMI spring. I have not experienced any more bulged cases since the spring swap in either caliber. Both run reliably with quality full power loads, my G20 load is 9.x grs of 800X under a 180gr nosler JHP. It is over book by .2 and runs well in my G20 with the heavy RSA. I live in south TX and only work up hand loads when summer heat sets in. So these loads show no pressure signs in my pistol. As far as out battery issues, I haven't experienced any such issues in any glock I own. The first thing I would suspect as to failing to go into battery would be the case dimensions, I use new starline brass as well and resize the brand new brass as well as run them thru a taper crimp after seating the bullet.

[jl1288]

After looking at those pics of the primer strikes again, looks like those are light loads. I went thru some of my reloading manuals and Lee 2nd edition shows 13.1 grains as a starting load for AA#9. Couple that with a heavier RSA and you might have some issues.

[I922sParkCir]

Howdy,
Those primer hits don't look like what a factory glock striker looks like to me.

It is a Glock striker! Definitely looks a little light.



The first thing I would suspect as to failing to go into battery would be the case dimensions, I use new starline brass as well and resize the brand new brass as well as run them thru a taper crimp after seating the bullet.

These were sized with a Hornady Custom Grade New Dimension sizer that has processed spent cases before. They also were run through a Lee Factory Crimp die. I did the "plunk test" with a handful. Don't suspect an issue there.

[I922sParkCir]

After looking at those pics of the primer strikes again, looks like those are light loads. I went thru some of my reloading manuals and Lee 2nd edition shows 13.1 grains as a starting load for AA#9. Couple that with a heavier RSA and you might have some issues.

Starting load is 13.1 grains with a 180 grain bullet? Accurate's load data (http://www.accuratepowder.com/load-data/) lists 12.1 grains of #9 as the starting load and 13.5 as the max. What is Lee's max?

I will chrono these, but unfortunately that requires a long drive to the desert.

[jl1288]

Lee's max is 14.5
Hopefully others will chime in on the issue. No lube in the striker channel? or any where else?

[I922sParkCir]

Lee's max is 14.5

Damn! Accurate has the velocity listed at 1260 for 13.5 with a pressure of 35,500. 14.5 sounds hot!



No lube in the striker channel? or any where else?

Only lubricated the rails, barrel around the muzzle and hood, locking block and connector.

Thank you for all of the information!

[I922sParkCir]

Related to the sights: Just got off the phone with Dawson. They said since the gun is shooting 2” high at 50” I need to have .345” tall front sight to replace the .300”. That is not a standard that they keep in stock, so they will have to make it. The tech said I should have it by the end of the week. Pretty impressed with their customer service and turn around.

[jl1288]

Dawson is generally pretty responsive at customer service. I have His sights on glock and a 1911. Yup that seems hot, the 800X is damn snappy. I bought some boutique 10mm that advertises 1300fps with a 180gr gold dot. Its shoots well in my G20 and I got curious and pulled 10 rounds down. It was stoked with 9.xgrs of what sure looks like 800X right down to the brown specks mixed in with the powder. I went down 10% and worked back up to what I measured out of the cases I broke down. I really need a chronograph, it is accurate enough for what I need.

[I922sParkCir]

Dropped in an ISMI stainless steel guide rod, 22lbs recoil spring, and the new .345" front sight.

I'm amazed at how much the recoil impulse has changed. Zero failures to fire, and now ejection is very consistent. The recoil has softened, and feels totally manageable. The slide velocity has noticeably slowed to what I would consider normal.

I even had an 1.5" group at 50 feet.

46819

Here was my progress at sighting in the gun:

46820
(Started counter clockwise from 5 o'clock)

I'm now very impressed with this gun.

[JasonB1]

Do you know anyone with a set of head space gauges? I once saw something similar with a friend's Glock 26 using 5 or 6 different types of factory ammunition ranging from Winchester white box to Corbon and Hirtenberger. Rarely could it make it through a magazine without failing to lock up with 3 different shooters who has no issues before or after with Glocks. Went back to Smyrna where it allegedly checked out fine with CCI Blazer, but when it returned it still has the failures to lock up and was traded back in to the FFL it was purchased from.

[I922sParkCir]

Do you know anyone with a set of head space gauges? I once saw something similar with a friend's Glock 26 using 5 or 6 different types of factory ammunition ranging from Winchester white box to Corbon and Hirtenberger. Rarely could it make it through a magazine without failing to lock up with 3 different shooters who has no issues before or after with Glocks. Went back to Smyrna where it allegedly checked out fine with CCI Blazer, but when it returned it still has the failures to lock up and was traded back in to the FFL it was purchased from.

Factory ammunition drops right into where it should, and they fall right out. No dragging or catching. Same with my hand loads. I inspected the chamber for any machining marks or burs that may cause issues feeding. I'm not quite sure if it's a chamber issue.

If the chamber wasn't reamed deep enough then the cartridge would sit too high. I could see this being a problem for the gun going into battery. The rounds in question sit exactly where they should.

If the chamber was reamed too deeply then the cartridge would index off of the extractor and I probably wouldn't notice an issue. It wouldn't be ideal, but it would continue to function.

The chamber appears to be in spec, although it's typical "Glock loose".

Thank you.

[Gödel]

A couple of things:

1. What site picture are you using to get 2" high at 50 feet? What sight picture does Dawson expect you to use?

2. Recoil springs are a trade off. They don't eat energy, so when you use a stronger recoil spring you are letting the takedown latch absorb the stored recoil forces instead of the frame. Don't go too heavy - Glock designed the gun with 17 lbs springs for a reason. Ejection distance isn't the measure of anything except the relative length of the ejector - not the velocity of the slide.

3. Off center strikes are out of battery strikes which are potential kaboom strikes. If your gun can't go into battery with a factory spring, it may be worth asking Glock some questions.

[I922sParkCir]

A couple of things:

1. What site picture are you using to get 2" high at 50 feet? What sight picture does Dawson expect you to use?


I'm using a center hold sight picture where the top of the front sight intersects the center of the target. Dawson did not seem concerned with what sight picture I should be using, they just asked me where my point of aim was in relation to the point of impact. They calculated a new front sight hight that would still give me some adjustment. Super impressed with my conversation with them.


A couple of things:
2. Recoil springs are a trade off. They don't eat energy, so when you use a stronger recoil spring you are letting the takedown latch absorb the stored recoil forces instead of the frame. Don't go too heavy - Glock designed the gun with 17 lbs springs for a reason. Ejection distance isn't the measure of anything except the relative length of the ejector - not the velocity of the slide.


Can you explain how the take down latch is subject to more force with the stronger spring? I'm trying to visualize, but I don't understand what you mean.

Regarding ejection: the ejection completely changed with the new spring. I pick up my brass and with the stock spring brass was forward, behind me, right in front of me, to my face and to the ejection port side. With this new spring there is a neat pile at about 4 O'Clock. The only exception is the last round in the magazine that ejects to about 2 O'Clock. Not quite sure what to make of that.

As an aside, this reminds me of my 4th Gen Glock 34 from 2011 that had a ton of ejection problems. I replaced every spring, put in the latest OEM Trigger Housing w/ ejector and still had tons of issues. Brass at most would just barely limp out of the gun, and stove pipe way too often. An Apex extractor helped and the White Sound H.R.E.D. finally solved it.



3. Off center strikes are out of battery strikes which are potential kaboom strikes. If your gun can't go into battery with a factory spring, it may be worth asking Glock some questions.

Absolutely. Out of battery strikes are very concerning. That's why I mentioned my friend should have known better.

I really hate reaching out to the manufacture. They are the experts and they are far more competent than I am at figuring out the problem, but sending it back is frustrating. They will probably get it, put a magazine though it, say it's fine, and send it back. I know a couple of people with that same experience with Glock who had to go to the aftermarket for solutions.

Thank you for the info!

[JasonB1]

Factory ammunition drops right into where it should, and they fall right out. No dragging or catching. Same with my hand loads. I inspected the chamber for any machining marks or burs that may cause issues feeding. I'm not quite sure if it's a chamber issue.

If the chamber wasn't reamed deep enough then the cartridge would sit too high. I could see this being a problem for the gun going into battery. The rounds in question sit exactly where they should.

If the chamber was reamed too deeply then the cartridge would index off of the extractor and I probably wouldn't notice an issue. It wouldn't be ideal, but it would continue to function.

The chamber appears to be in spec, although it's typical "Glock loose".

Thank you.

Best I can recall his 26 looked ok, but over and over it would stop just short of lockup.....squeezing the trigger would cause it to fully go in to battery with the high light primer hit not firing it.

[Gödel]

I'm using a center hold sight picture where the top of the front sight intersects the center of the target. Dawson did not seem concerned with what sight picture I should be using, they just asked me where my point of aim was in relation to the point of impact. They calculated a new front sight hight that would still give me some adjustment. Super impressed with my conversation with them.



Can you explain how the take down latch is subject to more force with the stronger spring? I'm trying to visualize, but I don't understand what you mean.

Regarding ejection: the ejection completely changed with the new spring. I pick up my brass and with the stock spring brass was forward, behind me, right in front of me, to my face and to the ejection port side. With this new spring there is a neat pile at about 4 O'Clock. The only exception is the last round in the magazine that ejects to about 2 O'Clock. Not quite sure what to make of that.

As an aside, this reminds me of my 4th Gen Glock 34 from 2011 that had a ton of ejection problems. I replaced every spring, put in the latest OEM Trigger Housing w/ ejector and still had tons of issues. Brass at most would just barely limp out of the gun, and stove pipe way too often. An Apex extractor helped and the White Sound H.R.E.D. finally solved it.



Absolutely. Out of battery strikes are very concerning. That's why I mentioned my friend should have known better.

I really hate reaching out to the manufacture. They are the experts and they are far more competent than I am at figuring out the problem, but sending it back is frustrating. They will probably get it, put a magazine though it, say it's fine, and send it back. I know a couple of people with that same experience with Glock who had to go to the aftermarket for solutions.

Thank you for the info!

I wondered about the sights because there are 3 common sight pictures. If you want center hold and you are sure that you want the pistol sighted in for 180s at 50" and that your groups reflect you best accuracy, then go for it.


Recoil springs don't make recoil go away. Recoil springs exist to return the slide to battery, and once the designer figures out how much force is needed to do that, everything else in the gun works on mass and frame impact. The G20 has the heaviest Glock slide mass. And a certain amount of the force of firing is supposed to go into the frame when the slide hits it. When you use a much stronger recoil spring the force that would normally be eaten by the frame impact gets stored in the spring, because the slide is no longer traveling all the way to the rear with the velocity it used to. Springs are very efficient, so all that energy comes back out of the spring when the slide goes into battery, and the take down latch is what stops the forward motion of the slide. You've also increased the velocity the slide is going when it strips the rounds, which can sometimes cause problems as your mag springs age.

The reason your empties don't eject as far isn't really lower slide velocity, it is just that the slide is no longer traveling fully to the rear. If you could make your ejector longer you could still launch the empties into outer space.


So now you've gone from a 17 pound spring to a 22. Whatever it was that was keeping the slide from closing isn't necessarily fixed or gone, but you have an extra 30% of spring force closing the slide so whatever it was is getting steam rolled. It probably isn't a problem, but it is a bit like using a hammer to fix the problem.


I'm sure plenty of people will disagree with nearly everything I've said, and it may not be a bad thing to up your recoil spring. Just consider that there is no free lunch and a spring is not a buffer.

[I922sParkCir]

Recoil springs don't make recoil go away. Recoil springs exist to return the slide to battery, and once the designer figures out how much force is needed to do that, everything else in the gun works on mass and frame impact. The G20 has the heaviest Glock slide mass. And a certain amount of the force of firing is supposed to go into the frame when the slide hits it. When you use a much stronger recoil spring the force that would normally be eaten by the frame impact gets stored in the spring, because the slide is no longer traveling all the way to the rear with the velocity it used to. Springs are very efficient, so all that energy comes back out of the spring when the slide goes into battery, and the take down latch is what stops the forward motion of the slide. You've also increased the velocity the slide is going when it strips the rounds, which can sometimes cause problems as your mag springs age.


Ohh, man! Of course the spring force goes into the take down latch upon the slide going forward. I didn't consider that. Mentioning the the slide picking up magazines is a good point as well. Everything you're saying is simple and intuitive, I just hadn't put it together. Thank you.





So now you've gone from a 17 pound spring to a 22. Whatever it was that was keeping the slide from closing isn't necessarily fixed or gone, but you have an extra 30% of spring force closing the slide so whatever it was is getting steam rolled. It probably isn't a problem, but it is a bit like using a hammer to fix the problem.



With 10mm there are higher pressure/higher velocity loads, and lower pressure/lower velocity loads. From what people have suggested the Glock is made to cycle relatively low powered factory ammunition like this Federal Hydra-Shok JHP traveling at 1030 (http://www.luckygunner.com/10mm-auto-180-gr-jhp-hydra-shok-federal-500-rounds) to this Underwood 10mm Auto 180 Grain XTP traveling at 1300 (https://underwoodammo.com/shop/10mm-auto-180-grain-xtp-jacketed-hollow-point/). It sounded like increasing the recoil spring optimizes the pistol for the "closer to original Norma spec" ammunition.




I'm sure plenty of people will disagree with nearly everything I've said, and it may not be a bad thing to up your recoil spring. Just consider that there is no free lunch and a spring is not a buffer.

That makes sense. A spring changes several different things where as the goal would just be to affect lock up time. Changing reciprocating mass like a buffer or a slide weight would be more effective.

So, I put in the original recoil spring and tried the RSA test again. It failed. I should have done the RSA test when I got the gun new.


https://youtu.be/4mMN-J1trno

I will reach out to Glock Monday. Hopefully they will just send me a new spring.

Thank you a ton. You've really helped me understand the situation.

[ST911]

Per the new armorer manual, RSA test is to be done at a 45 degree angle not on the vertical. When so conducted, what is the result?

Have you experienced any light strikes/OOB events with factory produced ammunition from a known-good manufacturer?

[I922sParkCir]

Per the new armorer manual, RSA test is to be done at a 45 degree angle not on the vertical. When so conducted, what is the result?


It fails the RSA test at 45 degrees. Actually, muzzle a little lower than 45 degrees.


https://youtu.be/MZKvJ3Vf0vA



Have you experienced any light strikes/OOB events with factory produced ammunition from a known-good manufacturer?

I have only shot 150 rounds of my handholds. The primers were seated on a progressive press, and are just under flush.

I do have some Underwood 180 grains and 200 grains but have not fired them. The primers were Federal Large Pistol Primers.

Thank you for the correction on the RSA test.