glock 20 not going into battery fully

Gents:

I have an 80% g20 that I finished up recently. I ended up with a rock slide usa windowed upper, a lone wolf alphawolf barrel, a wolff recoil spring and guide rod, and basically stock upper/lower parts kits.

Originally I was having a problem where the round wouldn't fully seat when chambering, and it was because I accidentally ordered a 13lb recoil spring somehow. I replaced that with a 17lb also from wolff, however its still doing the same thing. When the slide comes forward to strip a round off the mag, it will get the round in the chamber and the slide will move forward until the last 1/4" of travel. Basically, the portion of movement where the barrel ramps up to lock into the upper receiver. It will stop at that last little bit, and you have to give it a small nudge with your thumb to get it to go "click". Its not gritty or difficult, it just acts like it has alllllmost enough juice but can't quote do it. It did this to me 20 out of 20 shots.

I know its an 80%, but the pistols seem hard to screw up and I really don't think its super likely that this was my fault in drilling incorrectly somehow. Does anyone have any ideas? Do I need to polish the barrel lugs, or change anything in their geometry? I would think not, and also since they affect the timing of the action I would prefer not to change anything. Is it possible that I need to run a 20lb recoil spring?

I know some barrels can run "tight" from what I have heard, I am not sure if the alphawolf has this problem. I am pretty sure it is supposed to be a "drop in" barrel.

Sometimes you just need to oil them and rack the slide a few hundred or thousand times to break it in. They dont always fit perfectly right away.

so, not a G20 but nearly all G17/19 I built or had the opportunity to help had the part that sticks up on the trigger assembly that pushes on the firing pin safety too high.
The flaw is actually in the lower mold itself and really the only cure was to file down the bump on that trigger assembly.
I noticed the resistance even without rounds in the chamber but its worse with rounds in the chamber.
I have snap caps and some home made dummy rounds and I worked it until it was no longer pushing so much that pulling the trigger would raise up the slide some.

When you are normally shooting, your trigger is still pulled back when the slide returns. So w/o any round the chamber, pull the trigger back and hold it, then ease slide back and look for the slide to raise up some. If it does, its hitting that bump too high.

I know a slide should slam home, but even easing it back up, the slide should go all the way and the barrel lock up when there is no round in the chamber. YOu can see if this is a problem by removing the slide safety stop temporarily and see what happens before putting it back in.

What does the extractor look like? Does it function?

Make sure your slide lock spring is all the way flush with the inside channel. Sometimes they go in crooked and stick up a bit.


Also make sure the barrel drops easily into the slide while holding the slid upside down in your hand. If it doesn't, then you might have a little grinding or polishing to do.

What ammo? How are you sending the slide forward?

I was having this exact issue.

Polished the internal firing pin safety knob on the trigger assembly.

However, it still occasionally won't go fully into battery until I let up on the trigger.

Is this happening when you fire the pistol?

I found if I didn't keep very stiff wrists, the issue happened.

Haven't taken it back to the range for anymore debugging.

Melnic said:

so, not a G20 but nearly all G17/19 I built or had the opportunity to help had the part that sticks up on the trigger assembly that pushes on the firing pin safety too high.
The flaw is actually in the lower mold itself and really the only cure was to file down the bump on that trigger assembly.
I noticed the resistance even without rounds in the chamber but its worse with rounds in the chamber.
I have snap caps and some home made dummy rounds and I worked it until it was no longer pushing so much that pulling the trigger would raise up the slide some.

When you are normally shooting, your trigger is still pulled back when the slide returns. So w/o any round the chamber, pull the trigger back and hold it, then ease slide back and look for the slide to raise up some. If it does, its hitting that bump too high.

I know a slide should slam home, but even easing it back up, the slide should go all the way and the barrel lock up when there is no round in the chamber. YOu can see if this is a problem by removing the slide safety stop temporarily and see what happens before putting it back in.

Click to expand...

I had this with my first gen P80. Did lots on it and got it running like 98%. But about 1-2 rounds out of 100 it wouldn’t quite go in to battery and I’d need to tap the back of the slide slightly to seat it (started off at like 3 in 5 rounds). Building a V2 soon. How much did you need to take off? Like polishing amounts? Or like actually hitting it with a file some? Just file a little, test, file a little till it isn’t happening any more?

I’d like to get this one running 100%, or failing that at least 99.9%.

Thanks!

Pull out a round that chokes the pistol in the manner you are describing. Eject it. Feel the mouth of the case for burrs, etc.. If so, look for interference or binding during feeding. If this checks out...

Aftermarket barrel, remove the barrel and see if the ammunition drops into the chamber with a “plink” then drops free. Any lack of dropping from a sample of ten rounds or so means you need to finish ream the chamber.

17 pounds is for 40 S&W. 20+ is for 10mm.

17s and a 26 but done here, but the methods should be the same on the 20.

On each of my builds, barrels with fully supported chambers were used intentionally as I reload and wanted to minimize damage to my brass. Before installing, I took a little time to polish the edges and remove the sharpness from the chamber openings. One barrel had to be fitted to the slide but the others dropped right in. All OEM internal parts were used and polished prior to installation. Again, a few sharp edges were smoothed in the process. The top of the trigger arm that contacts the firing pin safety was rounded over on all of them.

They have eaten every 115, 124, and 125 grain round that they have been offered, and run smoothly. Haven't used any 147gn loads in them yet, but plan to eventually.

You may want to check the alignment of your slide rails, too. Here is another place where polishing can be of some benefit.

Lubrication should be used sparingly but if not enough is used, cycling problems are likely. As others have said, running a couple of hundred rounds through it should be sufficient for "break-in".

Hope you get it figured out.

lazarus said:

I had this with my first gen P80. Did lots on it and got it running like 98%. But about 1-2 rounds out of 100 it wouldn’t quite go in to battery and I’d need to tap the back of the slide slightly to seat it (started off at like 3 in 5 rounds). Building a V2 soon. How much did you need to take off? Like polishing amounts? Or like actually hitting it with a file some? Just file a little, test, file a little till it isn’t happening any more?

I’d like to get this one running 100%, or failing that at least 99.9%.

Thanks!

Click to expand...

Oh, it was like filing. I knew it was wrong cause I have a factory G17 gen 3. I could measure how it was off.

If you look at the removed slide, you can see the scrapes leading up to the safety plunger. What I did for each was to run the sharpie on the slide. Then work the slide with and without trigger held back. If it scrapes the slide, file it down. Repeat until not scraping. As always, little ad a time. I would not cut the slope until I had the height figured out with the sharpie first. Then filed the ramp, then sand, wet sand flitz it to get smooth.

One thing I could tell it was wrong was if you pull the trigger and squeeze more, the slide would move up and down. Another sign its too high.

Just remember, your filing the trigger assembly and that can NEVER go into another gun. Especially a factory Glock . Doing so, it may not operate the plunger and then not fire.

In the dozen or so that I have built and helped build, I have never had a need to 'file' down a trigger bar safety tab. If you aren't getting drag marks on the underneath side of the slide from it, I would leave it be, other than giving it and the bar itself a good polishing. While you're at it, give the drop safety button a good buffing as well. Usually, what the OP is describing is a problem somewhere else in the gun. Usually a problem in the op rod channel or a rail problem. That's been my experience.

I must thank everyone for the replies, you all are the best. There are too many to quote, so I will just address the points.

I actually noticed that the trigger in this gun felt "gritty" for lack of a better term. As in, when you pulled the trigger it was not a nice clean break. pressure would build, and sometimes it would break cleanly, sometimes it would creep towards a vague back wall and then break. I chased this for a bit, even put in an updated titanium drop safety (useless). In the end, I noticed that the face of the firing pin that the cruciform rides on was completely rough and had deep ridges. I reasoned that the dragging sensation would be the sear getting caught on the face, and sometimes it would hang on the ridges until you got past them. I polished the face with some diamond stones (carefully), and while its still the worst trigger I own its acceptable.

Part of chasing this issue was the drop safety bump. I did not file it "lower", but I did put a more rounded shape to it because I saw people recommending it. It did not seem to make a difference, but I can do the sharpie test and see whats going on. Its possible this is happening.

Slide lock spring is a good idea, I will check it. I definitely feel resistance from it when the back plate forces it to the side. I wonder if it is too far off where its supposed to be and giving too much drag but only at the end?

The ammo is Magtech (I know, its all I could find). Seems to go bang, drops into the barrel very easy and comes out when you flip it over. Barrel drops in and falls out of the slide without hesitation. (I will say, I did not examine any fired cases or chambered but unfired rounds since we were in a muddy field, that would be the next thing to check)

I guess I need to check the rail alignment (its a real possibility they aren't straight), check the slide lock safety, verify the drop safety bar isn't dragging on the slide, and see if it feels different. I will also probably order a another recoil spring (AGAIN ugh) since jimbobborg pointed out that 10 is supposed to be 20+.

After that, I need to fire it and see 1) what it does, and 2) what the cases and chambered but unfired rounds look like.

Also if anyone has any opinions on my gritty, crappy trigger, let me know what you would start looking at. I dont have a dremel so I still need to do the full polish, I will start there because I might as well...

A couple thought on the trigger- if you work on the sear engagement, proceed with caution. If you need to smooth the face on the cruciform, I've found that a super fine file works best. Remove as little material as necessary while maintaining the proper angle on it (sear face). I do not recommend using a dremel on that. There's too much risk of changing the angle, removing too much material, and or rounding the edges(which will result in decreasing surface area). In the end, you will want to have at least 2/3 to 3/4 of the sear face/firing pin engagement to be safe. You should buy one of these if you don't already have one https://www.glockstore.com/Glock-Armorers-Half-Slide-Cover-Plate
Is the firing pin an aftermarket product? Does it have a seam on it? If you can't fix that, you might consider a better firing pin.

Also, once you shoot some test rounds, check the brass for 'frosting' from a rough chamber. I had this problem with a Lone Wolf 10mm chamber. I was able to fix it with a buffing bit a Flitz. It runs and chambers fine now.

Glock OEM triggers are generally crappy even after polishing, but they are reliable. Lots of creep, but that is by design. If you can get it to be smooth with a clean and consistent break, the pull will still be 5 to 5.5 pounds. On a defensive weapon, quite acceptable.

Melnic said:

Oh, it was like filing. I knew it was wrong cause I have a factory G17 gen 3. I could measure how it was off.

If you look at the removed slide, you can see the scrapes leading up to the safety plunger. What I did for each was to run the sharpie on the slide. Then work the slide with and without trigger held back. If it scrapes the slide, file it down. Repeat until not scraping. As always, little ad a time. I would not cut the slope until I had the height figured out with the sharpie first. Then filed the ramp, then sand, wet sand flitz it to get smooth.

One thing I could tell it was wrong was if you pull the trigger and squeeze more, the slide would move up and down. Another sign its too high.

Just remember, your filing the trigger assembly and that can NEVER go into another gun. Especially a factory Glock . Doing so, it may not operate the plunger and then not fire.

Click to expand...

THANKS!

I wonder if that is what was troubling my P80 gen 1.5 in the end.

Anyway, I’ve got a V2 and a compact to build here at some point to make a G34 and 19. So I’ll for sure check that out. Good to know on the troubleshooting.

GuitarmanNick said:

Glock OEM triggers are generally crappy even after polishing, but they are reliable. Lots of creep, but that is by design. If you can get it to be smooth with a clean and consistent break, the pull will still be 5 to 5.5 pounds. On a defensive weapon, quite acceptable.

Click to expand...

IMHO, I don’t think they are that bad. Maybe I’ve just used ones that have a few thousand rounds on them, or slightly off spec (for instance mine has a lone Wolf reduced pull in my G17 and my G21 is a LE trade-in with probably maybe thousands of rounds on it).

I mean, it is NOT a fantastic trigger. But I’ve used many a worse striker fired gun and a few crappier DA guns.

Give me a nice SA or a really nice DA/SA gun any day of the week. But it doesn’t suck. And certainly doesn’t impact my ability to shoot it accurately or quickly.

Don't leave 10mm brass, someone here will be willing to pay cash for them.

Update on my PF45 in 10mm.

Installed 22# recoil spring. Most return-to-battery failures stopped, but still got a few.

After the range, saw a video of marinegunbuilder for the pf45 trigger housing. Like in the video, mine sat too high. A very quick sanding as in the video got it flush. That should get rid of the ejector rubbing the slide that I initially had.

However, running the "point straight up, ride slide" function still gets the slide out of battery.

Polished the rails, reseated pins.

Took out the striker safety (and ejector). This is to determine if the striker safety was the culprit. The same drill with just the striker assembly produced the same results, so I'm convinced it's not the striker safety hanging up on the trigger nub.

Thinking of trying an OEM glock 20 barrel. I have the alphawolf 20.3 barrel and the alphawolf g20 (oem look) slide.

I suspect the slide/barrel are hanging just enough to be causing problems.

I'm becoming disillusioned with 10mm simply because the damn thing is heavy with substantial recoil, even with 22# recoil spring.