P80 light strikes, failure to lock back

Hey, so I got my polymer 80 G17 to the range for the first time today. Pretty standard stuff for the build kit and Swenson non-threaded barrel and slide. Glock recoil spring assembly.

I ran most of a box of Remington 115gr UMC through it. Every other round was a light primer strike and it would successfully fire the round if I reloaded it. Also the slide was locking back on empty mags only about 20% of the time. Some miscellaneous handloads of JHP ran slightly better. Of 20 rounds I had 4 rounds (so happened twice) where I had two rounds fire successfully in a row before a light primer strike.

I loaded 15 rounds of Winchester 147gr JHP, definitely much stouter loads (white box) based on recoil. I had 1 light primer strike and it locked back successfully all 4 times (I loaded 2 rounds, fired them both. I loaded 3 rounds, fired them both. Then I loaded 10, 5 fired fine, light primer strike, next 4 fine, reloaded and fired the light strike again).

My best guess is something is causing some undue resistance on the slide. Maybe strong recoil spring and needs to be locked back for a few days to help out?

I noticed that the slide wouldn't lock in to battery properly all the time and the slide would need a tap to go in to battery. Not sure if that points more towards a slide/barrel fitment issue or if the wear point is somewhere else.

Maybe the thing just needs a few hundred rounds to break it in. I did just order 400rnds of mixed 124 and 147gr stouter loads (Mostly +P or NATO). See how well it runs with that and probably to help break it in better.

Thoughts? Nothing seems to be binding and it runs by hand just fine. Sling shoting it or releasing the slide with the slide release and it goes in to battery I think every time with a live round. There may have been one or two where I had to tap it. Since by the end I was loading each of my magazines (all 5) with a single round each.

Every single time it went bang properly when I ran the slide manually. So I think this is again pointing towards an issue with the slide not running all the way back either from resistance of the spring is too strong and it needs some break in.

Any help would be appreciated. I am going to attack the wear surfaces with some polishing compound for a bit and re-lube it. For the areas I milled the plastic (it is a V1.5) I am going to hit with some 400 grit as I only finished it with 220.

I have two P80 slide/barrel setups that have had light primer strike issues. One (an 80percentglock slide, which looks identical to a Swenson, and Brownells barrel) is worse that the other because the barrel and slide fitment is very tight. The barrel hood on that one doesn't actually sit flush with the slide. Here's a picture of the three slide/barrel combos I have. Notice how the hood on the stainless setup is not flush at the rear of the barrel hood like the other two:



On the bottom side, the barrel locking lug hangs down lower than it should and it requires the takedown lever to be depressed to get the slide mounted on the frame. Compare:



Light primer strikes in my cases are all due to the slide not fully going back into battery. I've learned to eyeball the barrel hood fitment in the slide after every shot. The shots where everything resets and the hood sits a millimeter or so lower than the slide are 99% going to be light strikes and a click instead of a bang.

I'd start by sanding and polishing the rails and making sure the recoil spring channel is fully open and very smooth. After that, generously lube the rails, other points of friction, including the lock up surfaces. Put some more rounds through it.

If you do that and still have issues (like I am), clean the barrel and inner slide surfaces. Use some Dykem (or just some light colored paint) to coat any areas where there may be fitment issues. In front of the barrel hood, rear of the barrel, etc. Assemble everything and work the action a bunch so that any points of contact that may require fitting get "marked". Then, slowly remove material with a flat, fine file (think just a couple passes) before retrying everything.

Here's a post where fitment of the slide stop of discussed:
https://www.mdshooters.com/showpost.php?p=5129424&postcount=45

This was posted on response to someone reportinh the opposite of the issue your having. Still, your slide failing to lock back may be due to an issue with how the slide lock lever/spring is installed. Do you use a very high grip on the frame? If so, you may also be interfering with the slide lock.

I am pretty sure it isn’t my grip as it is fairly low. I could be limp wristing it, but I don’t feel like I am. I don’t have a ton of pistol time, but never encountered it with other 9s, .40s or .45s.

I can’t reassemble the pistol without depressing the slide stop. Is it supposed to go back on without depressing the slide stop? I don’t have to depress it much, just a tiny bit.

With 100 rounds through it I have no idea what is normal wear, but it does seem to be wearing th Barrel hood a little and also oddly the rear notch on the barrel where it sits down in the locking block. That seems abnormal. The edge is actually very slightly rough now. That may have happened once as I stupidly assembled the thing without the recoil rod/spring when working on figment, but with the barrel and it jammed tight. It took several hard whacks on the rear of the slide to get it lose when it was stuck about an inch rearward.

The barrel and slide appear to lock forward in battery appropriately. I can look for that at the range next time to see if that is what is occurring or if it is low. There were a few times it failed to go fully in to battery and I had to whack the slide forward at the range. I can’t recall if those all went bang then or not. By hand if I press on the chamber I can get the barrel to depress about a millimeter. But it returns almost fully back to battery. Maybe .1-.2mm off “flush”

I out that in quotes as the barrel hood is slightly beveled/rounded on the front of my barrel so when the rear is basically flush (my finger nail barely catches) there is maybe a .3mm difference in height right at the front.

Pictures of wear points and what else I can think of attached.

I’ll take your suggestion and look at the areas and see what might need some sanding, light file work.

lazarus said:

I can’t reassemble the pistol without depressing the slide stop. Is it supposed to go back on without depressing the slide stop? I don’t have to depress it much, just a tiny bit.

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I can't help you with the problem, but I know that none of my Glocks require you to touch anything to reassemble them...My newly finished (100% Glock parts) G-17 P-80 doesn't either.

The slide stop/slide release should be (spring loaded) down and out of the way, unless you physically push it up...

Where does the slide stop "rest" when the slide is removed?

Is it sticking up, or is spring holding it down on the receiver like it should be?

So in reading what you wrote and doing more digging. Maybe it is the slide stop causing issues? I’ll have to look at how the spring is in the frame, but I have to press down like a son of a B on it to get the slide to come off. Okay, it isn’t that horrible, but I do have to press down HARD. For reassembly I have to press down lightly or the slide will not go back over it, it gets stuck about an inch forward of the assembled and in battery position

Never having disassembled and reassembled a Glock before this doesn’t sound normal. Sounds like there is too much spring tension on it. Beyond assembly/disassembly issues, could that be causing issues with drag on recoil preventing it from locking open and also the self loading light primer strikes (because it has fired successfully 100% or the slingshoted or slide release actuated slide closure times).

*edit* or maybe it isn’t an issue with the slide lock/take down. I just tried a few times just now and it will reassemble if I am careful without pulling down on the slide stop/take down lever and the leaf spring is well down in the channel.

Also disassembly is much easier pulling the trigger first, then pulling the slide back and the. Depressing the slide release. I’d been doing slide release then trigger. Doh! YouTube videos are great.

I guess I’ll look more closely at the wear points and what might be slightly out of spec. If the pictures make you think of anything, let me know. Thanks!

The slide stop spring should be routed as shown, under the top pin, as my "awesome" (lol) MS Paint diagram skills show...

You need to depress the trigger after verifying that the gun is unloaded, before trying to remove the slide. Press the trigger, slide the slide back very slightly, depress the slide lock and slide the slide forward. It should easily slide off, no effort required.

Chevelle is right, the slide stop spring needs to be 'under' the locking block pin and it should load the slide stop lever slightly in the down position. When you remove the slide, the lever should be down tight against the frame. The slide stop lever should only raise up when you do it manually, or the mag follower raises it on an empty mag. If you remove the slide, and slightly lift the stop lever, it should snap back down with a little spring tension.

The slide stop spring is circled in red, notice that it is 'underneath' of the upper locking block pin. You should install the top locking block pin before installing the trigger pin and slide stop and when sliding the slide stop in place, the spring will be in the correct position. If you install the trigger pin first, then the upper locking block pin next, you will likely have the spring in the wrong position..

It looks like the others have covered the slide stop lever spring and it's proper installation and orientation. That should help get you sorted out on that issue.

For the light primer strikes, I looked at your picture showing the barrel to slide fitment and it looks like the same fitment that my one setup has. I added a picture to post #2 above showing that slide and 2 others that I have. I also added a couple of pictures showing the barrel lug distance between two slides. The extra amount of distance that the lug hangs down is what requires me to depress the takedown lever to get this slide mounted on a frame.

I also remembered one other issue I've run into. On my first try as assembling a frame, the takedown lever spring was not properly installed. It was not sitting flush and the recoil spring would make contact with it. I'm not sure if that was contributing to the failures to go into battery/light primer strikes. Anything causing extra friction certainly isn't helping. Picture of the spring sitting flush:

It isn't the slide stop release, it is the take down one at the front of the gun that seems really tight.

Not the one you actuate to release the slide when locked back, but the one you pull down on to remove the slide from the lower.

The slide stop you use during normal operation rests down and out of the way with the slide off and doesn't seem to be the issue at all. I am wondering if the take down slide stop at the front might be too tight and causing some issues?

The highlighted bit is the one that I have some concerns about.

Additionally when assembling, the striker/striker safety cover on the back of the slide was really hard to get in to place. The firing pin channel liner seemed to be maybe a small fraction of a millimeter too long. I made pretty sure it was fully seated forward. The striker moves freely in the channel though and as mentioned, when manually operating the slide, it fires each time every time. I ran about 20 rounds through it single loading every magazine and no failures.

On the hood, if it isn't coming up flush, should I lightly file the flat part where it comes up against the slide? I'll try to get better pictures in an hour or two of the fitment from another angle as well as the lower barrel channel.

Is the takedown lever installed backwards? One of the sides has a little ledge. That is the side that should be facing the mag well. That could be why you have to pull down the takedown to install the side.

denimdan85 said:

Is the takedown lever installed backwards? One of the sides has a little ledge. That is the side that should be facing the mag well. That could be why you have to pull down the takedown to install the side.

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Nah ahhh....

Oh wait, damnit!

Yes, it was installed backwards. And a PITA to get out.

In properly now. It does reassemble smoother. Still have to pull down really hard to remove the slide, but not like inhuman amounts. More tiny ledges and strong spring kind of hard.

Any chance that could have messed it up with the light strikes? There doesn't seem to be a difference in terms of it going in to battery fully or not. Though I imagine I'd need to run ammo through it to really check that.

If you look closely at the barrel where it interacts with the takedown you will see there is a little lip. If the notch was not on the correct side of the takedown that could be keeping the slide from going fully into battery by a few thousandths and causing the striker to not make good contact with the primer. I never completed my v1 with the plastic rails and on my v2, it was stiff at first. I just used some bearing grease and racked the slide probably about 1000 times. It is now as smooth as my other Glocks.

I wouldn't remove any material until you test fire it again. You may have already fixed the issue. If you still have light primer strikes then pay close attention to how the barrel hood sits in the slide when your firing. See if you're running into the issue of slide not going fully into battery.

If your slide isn't going into battery fully then I'd degrease the barrel and slide and hit the areas that could potentially be binding up with some paint. The paint should show you where you need to remove material.

I need to do this same thing. Just haven't found the time.

Edit: found this video where the side of the barrel facing the slide needed fitting. So it may not need material removed from the front/rear. It may be the side(s).

Thanks guys! I looked at it some more yesterday and sat there for about 15 minutes racking the slide (should have worn gloves, my hands ache now). Nice and smooth now. I do think there is a difference in it going in to battery now. Not by much, but s few thousandths is a few thousandths.

I had also noticed in retrospect knowing what I had screwed up that accuracy was pretty bad. I am no marksman expert with handguns, but borrowing my neighbors handguns for a few rounds I could manage 2-3” 6 shot groups (mostly revolvers) at around 12-14 yards off hand. My 17 seemed to improve a tiny bit (I think mostly me) as I went through ammo, but it was still only doing about 5-6” groups at the same distance. If it wasn’t going fully in to battery and especially with different “not quite locked up” from round to round I’d imagine that could booger accuracy too.

And also now the month wait till I can get back to the range to test it out (too busy for a few weeks)