Diagnostic help: PX4 trigger drag in single action

[Earlymonk]

Howdy, all:

Just picked up the Compact today. Happy to have it and to begin squaring it away.

I hope some of you could help answer a question. I noticed (what is for me) a strange, gritty "drag" or "rub" on the initial SA takeup. Below are some short videos of the phenomenon.


https://youtu.be/4bHodvn4QhQ

With the slide off, it seems to have something to do with the trigger bar, the trigger bar spring, and the frame.


https://youtu.be/FIcCeQ-MnCk

Normal?

I suppose this could be right as rain, but it seems a little oddball to me... :confused:

[PX4 Storm Tracker]

Howdy, all:

Just picked up the Compact today. Happy to have it and to begin squaring it away.

I hope some of you could help answer a question. I noticed (what is for me) a strange, gritty "drag" or "rub" on the initial SA takeup. Below are some short videos of the phenomenon.


With the slide off, it seems to have something to do with the trigger bar, the trigger bar spring, and the frame.


Normal?

I suppose this could be right as rain, but it seems a little oddball to me... :confused:


Not normal. Your trigger bar is getting stuck and should not be down. This can happen more after cycling the slide, which pushes the trigger bar down.

You might try lubricating by the method mentioned in https://pistol-forum.com/showthread.php?29478-Beretta-PX4-Storm-45-High-round-count-long-duration-usage/page13 post #124. If this is not enough, other avenues of trigger bar stuck could be explored, such as sticking on the hammer pin spring. Might give this a try first.

You might also drop oil on the trigger to trigger bar connection.

[PX4 Storm Tracker]

I just tested our PX4 Compact to duplicate your issue. It has 12,000 rounds on it and is currently quite dirty. I could not duplicate the problem. The trigger bar never lowered, as your did.

[PX4 Storm Tracker]

Also, I would suggest checking that the trigger bar spring is securely in its slot https://pistol-forum.com/showthread.php?29665-Beretta-PX4-Storm-Parts-What-does-each-part-do-and-how/page3 post #21 Sometimes during cleaning it can pop out.

[farscott]

Just a WAG: Did you perform a full cleaning before trying the pistol? The protective liquid that Beretta applies before shipping is somewhat sticky and can cause malfunctions. A little bit of scrubbing with a good solvent and some lubricant are definitely required for any NIB Beretta.

[timotab]

Normal. My PX4CC and full size both do that. Unless you push the trigger forward or start to shoot in SA after racking the slide you would never feel this. I messed around with mine after I first got it and while annoying I've never noticed when shooting, which is what really matters.

[pangloss]

My PX4C does that too. I was curious about it, but I'm not convinced it's a problem.

[beenalongtime]

Is the pin for the trigger, completely through both sides, with both legs of the trigger spring behind the trigger? (two separate things, same sentence)
Is the trigger bar spring, behind the trigger bar, between it and the frame? (it looks like it moves more then mine, as it did when I had it rubbing once)

I've had to mess with the trigger pin before and on the advice/paste performance of another forum, I turned the pin around, which made me wonder if it is really one size or slightly tapered. This was for a sticky trigger.

[Earlymonk]

Thanks for the thoughts, fellas. So far "Normal" is ahead 2-1. Paging Ernest LangdonTactical! :)

The gun has been cleaned but has not been detail stripped. (Have to get some punches.) Alas, none of the cleaning suggestions above worked.

I did shoot a few more seconds of video.

Clearly the aft end of the trigger bar stays above the level of the frame throughout the DA pull.


https://youtu.be/XwhIPCHXQ14

It then is driven down below the level of the frame (emitting the grating squeak) as the hammer is cocked for SA. (And squeaks again as it comes back above.)


https://youtu.be/cqO-rSiVBlg

In this wider shot (so you can see the trigger) I repeated the squeak an extra few times for emphasis. :D


https://youtu.be/uKBrmJ8qm28

[Earlymonk]

Is the pin for the trigger, completely through both sides, with both legs of the trigger spring behind the trigger? (two separate things, same sentence)

Think I'm good on this. ^^^


Is the trigger bar spring, behind the trigger bar, between it and the frame? (it looks like it moves more then mine, as it did when I had it rubbing once)

Not so sure here. I've taken the tension off it and put it back twice, but I don't have much control (or visibility) when it goes back under the bar, so it could be going back to the same (wrong) place.

[pangloss]

I just looked closely at my pistol. The inside of the trigger bar is dragging on "wire looking thing" (technical term) shown in post 13 of PX4 Storm Tracker's thread (LINK (https://pistol-forum.com/showthread.php?29665-Beretta-PX4-Storm-Parts-What-does-each-part-do-and-how&p=704616&viewfull=1#post704616)). I think this part may be the hammer pin spring. That's my best guess based on a low resolution version of the Tekmat exploded drawing.

[PX4 Storm Tracker]

I just looked closely at my pistol. The inside of the trigger bar is dragging on "wire looking thing" (technical term) shown in post 13 of PX4 Storm Tracker's thread (LINK (https://pistol-forum.com/showthread.php?29665-Beretta-PX4-Storm-Parts-What-does-each-part-do-and-how&p=704616&viewfull=1#post704616)). I think this part may be the hammer pin spring. That's my best guess based on a low resolution version of the Tekmat exploded drawing.

You're right. That is the hammer pin spring. By the sound of the squeak one can often guess what thickness of metal is rubbing which. That spring is a frequent culprit. If you notice in post #23 of https://pistol-forum.com/showthread.php?29478-Beretta-PX4-Storm-45-High-round-count-long-duration-usage/page3 the part of the trigger bar that rubs against the frame by it is getting a lot of friction. This would make for 2 more spots to lubricate.

[Earlymonk]

That is the hammer pin spring. ...That spring is a frequent culprit.

I'm thinking friction on the hammer pin spring may be my culprit too.

Wondering if folks are describing that as normal because:


a) it's part of the design.
or
b) it's something that frequently needs attention.

If it's a) I guess I just need to lube it?
If it's b) what do you recommend as a fix?



...the part of the trigger bar that rubs against the frame by it is getting a lot of friction. This would make for 2 more spots to lubricate.

Given that the wear from trigger bar v. frame seems inevitable, the "2 spots to lube" comment has me leaning towards "it's also supposed to rub on the hammer pin spring." Am I reading that wrong? :confused:

[beenalongtime]

I just looked closely at my pistol. The inside of the trigger bar is dragging on "wire looking thing" (technical term) shown in post 13 of PX4 Storm Tracker's thread (LINK (https://pistol-forum.com/showthread.php?29665-Beretta-PX4-Storm-Parts-What-does-each-part-do-and-how&p=704616&viewfull=1#post704616)). I think this part may be the hammer pin spring. That's my best guess based on a low resolution version of the Tekmat exploded drawing.

I wonder if that spring is fully seated in the pin, and not pressed down a bit where it would rub/catch the trigger bar.
Back to that picture, linked above. EL's TJIAB, which is part of what I based lubrication points for my other guns, lubes/greases the tension pin for the spring tails (you did put that spring in polished side towards the cup I hope), as well as in between the sear and the hammer. I actually asked him in another thread about lube on the hammer pin, and didn't receive a reply, so I have put some on one of my guns for my next range trip, which I hope Tuesday will be (if not it may be a while as spring projects/house painting is going to take up free time).
You can push down that spring, there by pushing out the top pin, via the back side (backstrap side) of the gun. See EL's hammer replacement video, for about the best video to be able to understand.

Last night in a dream, made me come back and read both your threads, as my brain was saying you said you ordered a PX4"c" and I wasn't sure if you ordered a normal gun and tried to put a TYPE C parts in it, or you ordered the compact. The trigger bars are different between those.

[PX4 Storm Tracker]

I'm thinking friction on the hammer pin spring may be my culprit too.

Wondering if folks are describing that as normal because:


a) it's part of the design.
or
b) it's something that frequently needs attention.

If it's a) I guess I just need to lube it?
If it's b) what do you recommend as a fix?



Given that the wear from trigger bar v. frame seems inevitable, the "2 spots to lube" comment has me leaning towards "it's also supposed to rub on the hammer pin spring." Am I reading that wrong? :confused:

Normal is a relative term. Normal might mean that most Compacts do that. It does not prove that it is acceptable. Perhaps Beretta has a run of trigger bars that are different or frame casting issues.

The design is good. We have over 90,000 rounds on PX4s and so little trouble from hammer pin springs. However, here’s one thing I’ve noticed: Often when cleaning in front of the rear right frame rail, behind the trigger bar, folks will insert a rag or patch and unknowingly push the top bar of the spring downward. The top leg drags on the hammer assembly and could stay down, changing its position. After cleaning I like to take a small skewer or punch and hook the top bar of it and snug it upward.
I have had to replace 2 hammer pin springs because of loosening. The indication was a hammer pin drifting, but never a problem like you are experiencing.
Tugging up on it gently and lubricating it and the other side of the trigger bar might help. If the spring stays down it might need replacement.

It will rub on the spring a little, that is normal. But, something is forcing your trigger bar to drop down, that is not right. Only the slide or right safety lever should do that. https://pistol-forum.com/showthread.php?29665-Beretta-PX4-Storm-Parts-What-does-each-part-do-and-how&p=704616&viewfull=1#post704616 posts 19-22

[fixer]

I just looked closely at my pistol. The inside of the trigger bar is dragging on "wire looking thing" (technical term) shown in post 13 of PX4 Storm Tracker's thread (LINK (https://pistol-forum.com/showthread.php?29665-Beretta-PX4-Storm-Parts-What-does-each-part-do-and-how&p=704616&viewfull=1#post704616)). I think this part may be the hammer pin spring. That's my best guess based on a low resolution version of the Tekmat exploded drawing.

Yes. The Hammer pin spring, the wire looking thing, rubs on the trigger mechanism making a squeak. All 5 of my old PX4s did this.

[PX4 Storm Tracker]

Additionally, according to your videos, the trigger bar is not dropping down on double action because the hammer's double action hook is maintaining pressure on it.
Also your video indicating the pressure you need to finish pushing the trigger forward is not much. This would indicate a small rubbing or deflection not caused by a heavy immobile part.

[BobLoblaw]

The trigger bar dragging against the frame is normal and it’s more pronounced when new. You don’t notice it in live fire. The squeak is abnormal.

[pangloss]

Yes. The Hammer pin spring, the wire looking thing, rubs on the trigger mechanism making a squeak. All 5 of my old PX4s did this.

In your experience, did the trigger bar rubbing the hammer pin spring ever result in any problems? It's a little annoying, but I don't see how it really hurts anything. However, I'm new to the platform, so I don't put much stock in my opinion on the matter.

[fixer]

In your experience, did the trigger bar rubbing the hammer pin spring ever result in any problems? It's a little annoying, but I don't see how it really hurts anything. However, I'm new to the platform, so I don't put much stock in my opinion on the matter.

In live fire I didn't notice it.

The highest round count I got to was a shade under 30k on a single 9mm full size. This issue got a little bit less pronounced versus the newer pistols I had at the time. So there is some 'wear-in' that can mitigate the issue but only about 25%.

The other data point that made me realize it wasn't a huge issue was it persisted across multiple caliber lines and different years. I had 3 9mm full size, 0.40, and 0.45 all from different years and they all did it.

[Earlymonk]

Just rounding back with word from a factory rep on this. He wrote:


Fairly typical. Ensure that the spring is up and lubricate all contact points. We put a preservative on during assembly that is NOT a lubricant and it can exacerbate contact noises.

So it's an issue some/most of the time. That seems like a design flaw but not a significant one. YMMV.

Maybe installing the LTT TIB would eliminate the rub?

[PX4 Storm Tracker]

In live fire I didn't notice it.

The highest round count I got to was a shade under 30k on a single 9mm full size. This issue got a little bit less pronounced versus the newer pistols I had at the time. So there is some 'wear-in' that can mitigate the issue but only about 25%.

The other data point that made me realize it wasn't a huge issue was it persisted across multiple caliber lines and different years. I had 3 9mm full size, 0.40, and 0.45 all from different years and they all did it.

This is excellent feedback! I like reading about high round counts on PX4s.

I have never experienced the sticking trigger symptom on any Storm, including ours, students' and pistols inspected, about 20 or more. I have had a couple that squeaked. I put a drop of oil on the sides of the hammer where it pivots and that fixed that. On my wife's Compact the squeak persists under thumb cocking, probably the hammer pin spring or drag of the sear on the hammer face. @12,300 rounds it works just fine, though.

I read your comment and read what you were answering- to clarify: you're writing about the squeak from the hammer pin spring? Or are you also writing that your Storms had a sticking trigger that moved the trigger bar down, etc., as described in the videos in the thread?

[LangdonTactical]

I have seen this kind of thing with many different guns, not just PX4s or Beretta pistols. I have worked in the industry for many years, and people get a new gun and sit around and pull the trigger really slow, play with the trigger with the slide off of the gun, feel for a listen to every noise that the gun makes. Often, none of this stuff affects function or reliability of the gun, it is just something they found when they were "playing" with their new gun.

I am not denying the fact that some of these issues are annoying, but we may be getting OCD about things on a $450 to $800 handgun that is a "service pistol".

If you want an absolutely perfect handgun, go buy yourself a Wilson Super Grade at about $8,000. Or better yet, you can get Jason Berton to build you a 1911. They start at $12,000 and take about 3 to 4 years to get, but they are absolutely flawless!

[PX4 Storm Tracker]

Just rounding back with word from a factory rep on this. He wrote:



So it's an issue some/most of the time. That seems like a design flaw but not a significant one. YMMV.

Maybe installing the LTT TIB would eliminate the rub?

I have dealt with Beretta for years on different levels of service. Sometimes they answer the part they focus on or the part they want to answer. I've learned to ask more after an initial answer. With that in mind, as I read your quote from them, it seems they answered about the squeak. Did they answer about the sticking trigger and dropping trigger bar specifically? Or is my understanding of their answer unclear?

[Earlymonk]

...people get a new gun and sit around and pull the trigger really slow, play with the trigger with the slide off of the gun, feel for a listen to every noise that the gun makes. Often, none of this stuff affects function or reliability of the gun, it is just something they found when they were "playing" with their new gun.

I am not denying the fact that some of these issues are annoying, but we may be getting OCD about things on a $450 to $800 handgun that is a "service pistol".


Really appreciate your weighing in on this, Ernest. Glad to know that this sort of thing is relatively common in your experience--and irrelevant to function or reliability.

My experience is ONLY with service pistols in the lower price range, and I've not run into a "minor internal oddity" like this with Glocks or M&Ps. (And with almost any mechanical device, I'll certainly own up to the "OCD player" profile!)


...it seems they answered about the squeak. Did they answer about the sticking trigger and dropping trigger bar specifically?

No, not specifically. I take the reply to mean that the symptoms in their totality are "fairly typical."

[PX4 Storm Tracker]

I have seen this kind of thing with many different guns, not just PX4s or Beretta pistols. I have worked in the industry for many years, and people get a new gun and sit around and pull the trigger really slow, play with the trigger with the slide off of the gun, feel for a listen to every noise that the gun makes. Often, none of this stuff affects function or reliability of the gun, it is just something they found when they were "playing" with their new gun.

I am not denying the fact that some of these issues are annoying, but we may be getting OCD about things on a $450 to $800 handgun that is a "service pistol".

If you want an absolutely perfect handgun, go buy yourself a Wilson Super Grade at about $8,000. Or better yet, you can get Jason Berton to build you a 1911. They start at $12,000 and take about 3 to 4 years to get, but they are absolutely flawless!

Ernest, It appears that you are saying that little squeaks and rubs are acceptable in an inexpensive service pistol. Ok... But are you only addressing the squeaking here or are you also saying that if the trigger does not go all the way forward and you must put your finger behind it and help it go forward.. that that is acceptable?

[LangdonTactical]

Ernest, It appears that you are saying that little squeaks and rubs are acceptable in an inexpensive service pistol. Ok... But are you only addressing the squeaking here or are you also saying that if the trigger does not go all the way forward and you must put your finger behind it and help it go forward.. that that is acceptable?

I am not saying either really. I agree that a squeaking in the trigger is annoying, and he may have a real issue here, I really don't know without seeing the gun.

But, if you are pulling the trigger in a manner in which the gun was not meant to function, then weird things can happen. Guns will do all kinds of weird things if you try to make them do it. For example, I have heard the "when cycling the slide by hand and let the slide go forward really slowly, sometimes it does not go all the way into battery".

Again, I am not saying he does not have an issue. But it seems to not be an issue when he is shooting the gun, or when cycling the slide hard or when shooting at speed, so....? It also looks like he has to release the trigger pretty slowly to get it to "stick".

None of my guns do this, I have tried all of them. I will give it a shot on a new batch of full-size PX4s when I get them.

[PX4 Storm Tracker]

I am not saying either really. I agree that a squeaking in the trigger is annoying, and he may have a real issue here, I really don't know without seeing the gun.

But, if you are pulling the trigger in a manner in which the gun was not meant to function, then weird things can happen. Guns will do all kinds of weird things if you try to make them do it. For example, I have heard the "when cycling the slide by hand and let the slide go forward really slowly, sometimes it does not go all the way into battery".

Again, I am not saying he does not have an issue. But it seems to not be an issue when he is shooting the gun, or when cycling the slide hard or when shooting at speed, so....? It also looks like he has to release the trigger pretty slowly to get it to "stick".

None of my guns do this, I have tried all of them. I will give it a shot on a new batch of full-size PX4s when I get them.

A very clear explanation, thanks. I fully agree.

It is also reassuring that when getting a PX4 from LTT you get the added layer of safety and function inspection.

[LangdonTactical]

It does look and sound like your hammer pin spring is rubbing on the trigger bar. But none of the videos show a view down into the frame in that area.

I have seen similar issues on guns where someone detail stripped the gun and bent that spring causing it to rub the trigger bar.

So if it has never been detail stripped, I don't know what is going on there without seeing the gun.

[Earlymonk]

But, if you are pulling the trigger in a manner in which the gun was not meant to function, then weird things can happen.

Wasn't doing anything terribly odd when I discovered it; in fact, the initial "grating" in the SA was pretty apparent, compared to anything else I've shot. It was only after feeling that fingers-on-a-chalkboard sensation at the beginning of the take-up that I started looking more closely.


Again, I am not saying he does not have an issue. But it seems to not be an issue when he is shooting the gun, or when cycling the slide hard or when shooting at speed, so....?

To be clear, the gun has not been shot yet. I've got a class this weekend (and a backup gun!) and will report back.


It does look and sound like your hammer pin spring is rubbing on the trigger bar.

Pretty sure this is the situation. I'm getting the sense that it's maybe not supposed to! :)


I have seen similar issues on guns where someone detail stripped the gun and bent that spring causing it to rub the trigger bar.
So if it has never been detail stripped, I don't know what is going on there without seeing the gun.

Gun has never been detail stripped. It exhibited this behavior as soon as it came out of the box. I'm thinking it may be making a trip to Gilbert, AZ soon...:cool:

[PX4 Storm Tracker]

Is the pin for the trigger, completely through both sides, with both legs of the trigger spring behind the trigger? (two separate things, same sentence)
Is the trigger bar spring, behind the trigger bar, between it and the frame? (it looks like it moves more then mine, as it did when I had it rubbing once)

I've had to mess with the trigger pin before and on the advice/paste performance of another forum, I turned the pin around, which made me wonder if it is really one size or slightly tapered. This was for a sticky trigger.

The trigger pivot pin is equal on both sides. However, the spring will move it off center to a spot it likes. I've recentered many trigger pins, only 2 have stayed centered. Since the spring makes diagonal marks in the Bruniton, it appears to torque a little to a side it likes. It is probable in your instance that you mentioned, that it was torquing too much. Another issue I've noticed (though I'm not hinting that you did this) is that people use punches and hit the trigger pivot pin through. The inner ledges of this pin make that inadvisable. I prefer to depress the spring and wiggle it through. When in the right spot and angle it will walk right in.

[PX4 Storm Tracker]

Not so sure here. I've taken the tension off it and put it back twice, but I don't have much control (or visibility) when it goes back under the bar, so it could be going back to the same (wrong) place.

A way to check if the trigger bar spring is in its slot is to slide a piece of paper between it and the frame. If you feel the spring hit the paper, you're not in. The other side can be observed visually. Also, if it doesn't wiggle separately, you're in.

[PX4 Storm Tracker]

There is some distance that is made by the hammer frame unit to avoid excessive contact of the trigger bar with the hammer pin spring. Slight rubbing under vibration or gentle rubbing might occur.

Notice in https://pistol-forum.com/showthread.php?29665-Beretta-PX4-Storm-Parts-What-does-each-part-do-and-how/page2 post #13 that the stud under which the bottom curve of the hammer pin spring locks protrudes pretty far. This combined with the built in spacer bar higher up (visible in post #17) maintain the work space for the trigger bar to move around in.

Side note: The hammer pin spring upper leg in this picture is sitting too low and I replaced it.

[timotab]

I've owned 3 PX4's, 2 were used 1 was bought new, and they all did/do this.........but only if pressure was applied to the trigger pushing it towards the muzzle, the opposite from what you would normally do when shooting, OR when starting to shoot by either manually cocking the hammer or performing a slidelock reload. a little oil or grease on the side of the trigger bar will make it less pronounced but the only time I ever noticed it was during dry fire. The trigger return spring does not reset the trigger to a point where the trigger bar and hammer retaining spring touch on my guns.

[pangloss]

It does look and sound like your hammer pin spring is rubbing on the trigger bar. But none of the videos show a view down into the frame in that area.

I have seen similar issues on guns where someone detail stripped the gun and bent that spring causing it to rub the trigger bar.

So if it has never been detail stripped, I don't know what is going on there without seeing the gun.

Here's a video of my pistol (LINK (https://photos.app.goo.gl/WFDtNbTRDCJf21hB3)), though I'm not sure how much additional information it'll provide. My PX4C has ~350 rounds through it. I have not detail stripped it, but I have applied lubricant between the hammer pin spring and the trigger bar. I can pull the trigger pretty quickly to the wall just before SA hammer release, and the trigger does not fully return to the forward position. If I pull the trigger, keep it depressed, and run the slide by hand, the trigger does not fully return to the forward position. If I pull the trigger, release it, and then run the slide, the trigger does go fully forward. During the trigger pull, the squeak occurs when the rear end of the trigger bar is moving vertically. Once the forward motion begins, the squeak stops. When I release the trigger, the trigger bar travels fully backwards but not down. Applying a little pressure to the back of the trigger causes the rear of the trigger bar to drop to the normal resting position.

Please don't interpret my description as a complaint or gripe about the pistol. I really like this pistol, and I don't think the squeak is significant issue. Probably half my shooting with it so far has been in DA, and I haven't noticed the squeak during SA fire.

[LangdonTactical]

Gun has never been detail stripped. It exhibited this behavior as soon as it came out of the box. I'm thinking it may be making a trip to Gilbert, AZ soon...:cool:

This is something I know that I can fix if the gun is in my hands!

[Earlymonk]

This is something I know that I can fix if the gun is in my hands!

I have NO doubt that you could, and then some! Stop tempting me, Langdon! :) LOL

Matter of fact, I was emailing with your lovely wife about that very thing, but the fact that the two-way shipping triples the cost (!) backed me away from the ledge a little bit. (However, the deterrent effect may not be lasting...)

[MMcCall]

I just got a new Compact, and mine does the same thing.. it's annoying, but I figured I would clean/lube/shoot it and see if I still noticed, or if it caused any problems. I don't anticipate that it would.

My slide/frame fit is also *really* loose on this pistol, it kind of surprised me since it's an Italian gun and they generally seem to be a bit higher quality.

[PX4 Storm Tracker]

Out of curiosity, could anyone that is having a problem with your Compact doing the sticking trigger find out, either by calling Beretta with your serial number, or at least looking on the side of the slide, on the rear right, for an IT date. I would be curious if there is a connection between when they were made and this issue.

Ours is 2014 and does not have this issue.

[Earlymonk]

Out of curiosity, could anyone that is having a problem with your Compact doing the sticking trigger find out...an IT date.


By this: http://www.berettasupport.com/applications/tech_data/schematics_search_new.htm
And by the slide IT date:

2017

[PX4 Storm Tracker]

By this: http://www.berettasupport.com/applications/tech_data/schematics_search_new.htm
And by the slide IT date:

2017

Nice Avatar.

[PX4 Storm Tracker]

The IT date will say when the slide was manufactured. It will be an approximation of when the pistol was assembled. The serial number can tell you when it was assembled.
If we find that there is a similarity of dates, then we can check the frame lot numbers and if we find a similarity we may find a problem that Beretta can address.

[m.mancini]

One data point from my side, I have experienced the same grittiness on my PX4 manufactured in 2014, specifically when manually cocking the hammer and applying pressure on the trigger, and to a lesser extent approximately in the middle of the DA stroke (during the DA stroke there was no squeaking but the grittiness was noticeable, starting approx at 1/3 of the pull and disappearing for the last third of the pull before hammer release).

Upon inspection of the frame, looking from the top at the trigger bar, it looked to me as well as if the trigger bar is making contact with the hammer pin retaining spring, and it looked like the spring is misplaced since it had a lot of free movement when touched with a small screwdriver. Keep in mind up to this point I never fully disassembled the PX4 frame.

Upon disassembly of the frame and inspection of wear on the trigger bar and spring, I noticed the trigger bar, in the portion of the pull that interests us, is sliding against the head of the pin/stud (for lack of a better word) that is used to secure the hammer pin retaining spring. This looks like is a removable part but in the factory drawing it looks like is considered an integral part of the hammer unit housing. Out of curiosity, I've lightly polished the head of this pin, as well as the affected part of the trigger bar, and it DOES improve on the feeling of the trigger. It looks like to completely eliminate the squeaking after manually cocking the hammer, one would need to sand away approximately 0.5mm (pardon the EU unit of measure, approx. 0.02 inches) of material from the head of that pin.

I did not proceed further with experimenting or with sanding/polishing since in my opinion this is not a big deal (I could only feel it during dry firing AND paying attention to it) and IMHO it looks like it doesn't affect the functioning of the gun in any way. In fact the issue, if unnoticed, may go away simply by cycling the trigger enough times when firing ?

Photos of the pin head below, marked in red.

25597

[PX4 Storm Tracker]

One data point from my side, I have experienced the same grittiness on my PX4 manufactured in 2014, specifically when manually cocking the hammer and applying pressure on the trigger, and to a lesser extent approximately in the middle of the DA stroke (during the DA stroke there was no squeaking but the grittiness was noticeable, starting approx at 1/3 of the pull and disappearing for the last third of the pull before hammer release).

Upon inspection of the frame, looking from the top at the trigger bar, it looked to me as well as if the trigger bar is making contact with the hammer pin retaining spring, and it looked like the spring is misplaced since it had a lot of free movement when touched with a small screwdriver. Keep in mind up to this point I never fully disassembled the PX4 frame.

Upon disassembly of the frame and inspection of wear on the trigger bar and spring, I noticed the trigger bar, in the portion of the pull that interests us, is sliding against the head of the pin/stud (for lack of a better word) that is used to secure the hammer pin retaining spring. This looks like is a removable part but in the factory drawing it looks like is considered an integral part of the hammer unit housing.

An excellent observation. It is also a very frequent culprit. You are also correct that it is not a user replaceable part (semi-permanent installation). Since many Storms don't squeak or rub, it is possible that something in the frame is pushing it to rub too hard on this peg. The trigger bar drag marks might suggest that this is what pushes erring trigger bars down. That remains on my primary suspect list.

Light polishing, as you mentioned, can surely help if done carefully. This peg also serves to maintain the trigger bar's alignment with the hammer and sear. If too much metal is removed, misalignment could occur. Dropping some oil to drip down the trigger bar to this area could help a person determine if their pistol is being affected by this rubbing.

The good news is... on all of my PX4s with moderately high round counts this area self polished pretty well.

[m.mancini]

Agree, after spending some more time looking at the PX4 trigger group, it is definitely a bad idea to do anything more than a light polish in that area, since it keeps the trigger bar from flexing and in alignment, as you said.
I'm about to order a competition trigger group anyway, curious to see if it will solve the issue with the sticky trigger bar. If not, no big deal.

[PX4 Storm Tracker]

Agree, after spending some more time looking at the PX4 trigger group, it is definitely a bad idea to do anything more than a light polish in that area, since it keeps the trigger bar from flexing and in alignment, as you said.
I'm about to order a competition trigger group anyway, curious to see if it will solve the issue with the sticky trigger bar. If not, no big deal.

Cool. I would be curious how the Competition Trigger group affects things.

[PX4 Storm Tracker]

m.mancini , If you still have your hammer assembly out, could you inspect the cut out in the frame where the trigger bar rides for anomalies?

[m.mancini]

m.mancini , If you still have your hammer assembly out, could you inspect the cut out in the frame where the trigger bar rides for anomalies?

Looks clear of defects/burrs.

[PX4 Storm Tracker]

Food for thought about this trigger sticking...

When the hammer is pulled back by hand or by the slide, the hammer’s cocking cog pushes the trigger bar downward and forward.

See- https://pistol-forum.com/showthread.php?29665-Beretta-PX4-Storm-Parts-What-does-each-part-do-and-how post #3, bottom most pointer & post #4- top picture, right pointer.


This keeps the trigger bar from accidently bumping the sear while being thrown forward. https://pistol-forum.com/showthread.php?29665-Beretta-PX4-Storm-Parts-What-does-each-part-do-and-how/page2 post #17

When the trigger moves forward it lets the trigger bar pop up (with a slide in battery or no slide on). If the trigger bar’s peg is relieved of that pressure (from the hammer) it pops up.

If the hammer's work space and the trigger bar’s are impeded with burrs or excessive debris, the trigger bar could get stuck there, creating a “sticking trigger” during reset. https://pistol-forum.com/showthread.php?29665-Beretta-PX4-Storm-Parts-What-does-each-part-do-and-how/page2 post #13

[medmo]

Not normal. Assembled incorrectly? Google Px4 disassemble/re-assemble and carry it out with your pistol would be my suggestion. Possibly the trigger bar spring? Needs a lot send back to BUSA if this doesn’t get resolve it or you don’t want to play gunsmith.

[PX4 Storm Tracker]

Earlymonk , Any progress on this problem since?

[pangloss]

I've made some additional observations. I put a competition trigger group in my gray PX4C and the trigger bar drags across the retaining spring just like it did in the original configuration. I also bought a PX4CC and the same thing happens with it. So my personal stats are that this occurs in three of three trigger groups.

[PX4 Storm Tracker]

I've made some additional observations. I put a competition trigger group in my gray PX4C and the trigger bar drags across the retaining spring just like it did in the original configuration. I also bought a PX4CC and the same thing happens with it. So my personal stats are that this occurs in three of three trigger groups.

Did these three also have the sticking trigger symptom?

[pangloss]

Did these three also have the sticking trigger symptom?

Yes.

[PX4 Storm Tracker]

Yes.

These observations are most informative, thanks.

[pangloss]

The only other thing I've noticed is that in the gray PX4C, there is a slight gap between the end of the hammer pin spring and the trigger mechanism frame. If the hammer pin spring was bent in just a little bit--about the distance of that gap, it might be enough to cure the sticking trigger. Next time I order parts, I'll get an extra spring and see if I can "fix" it.

[PX4 Storm Tracker]

The only other thing I've noticed is that in the gray PX4C, there is a slight gap between the end of the hammer pin spring and the trigger mechanism frame. If the hammer pin spring was bent in just a little bit--about the distance of that gap, it might be enough to cure the sticking trigger. Next time I order parts, I'll get an extra spring and see if I can "fix" it.

In post #13 of https://pistol-forum.com/showthread.php?29665-Beretta-PX4-Storm-Parts-What-does-each-part-do-and-how/page2 you can see that one end tucks into a slot and the other is pressed against the hammer unit frame. Are you thinking of lessening the curved out area of the top bend? Or are you saying that in yours the top end is not pressed against the unit?

[pangloss]

In post #13 of https://pistol-forum.com/showthread.php?29665-Beretta-PX4-Storm-Parts-What-does-each-part-do-and-how/page2 you can see that one end tucks into a slot and the other is pressed against the hammer unit frame. Are you thinking of lessening the curved out area of the top bend? Or are you saying that in yours the top end is not pressed against the unit?

The top end on my spring is not pressed against the unit. I'll try bending the spring just enough that the top end touches the trigger mechanism frame.

[PX4 Storm Tracker]

The top end on my spring is not pressed against the unit. I'll try bending the spring just enough that the top end touches the trigger mechanism frame.

That is most unusual. It could even be the source of the problem. That should not only be touching the frame, but pressing on it under pressure.

[pangloss]

That is most unusual. It could even be the source of the problem. That should not only be touching the frame, but pressing on it under pressure.

I noticed the little wear spot on the trigger mechanism frame pictured in post #13 that you linked to above. In my gray pistol I can see the end of the pring flext during the early stages of trigger pull, and it appear the it does contact the trigger mechanism frame after the trigger bar rises during the initial stage of the pull. In the PX4CC, I can't see a gap at the end of the spring. For both pistols, if I point the frame toward me and look down into the action from the front, it looks like the trigger bar is rubbing against the little post that the hammer pin spring wraps around. Very interesting. I'd not noticed that before.

[pangloss]

For both pistols, if I point the frame toward me and look down into the action from the front, it looks like the trigger bar is rubbing against the little post that the hammer pin spring wraps around. Very interesting. I'd not noticed that before.

Or I could have just read post #43 in this thread...


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