Need Advice: Beretta PX4 Slide not locking after last shot

[eswrite]

This issue concerns a new Beretta PX4, with 4 new Beretta 10 round magazines. I've shot it now in two sessions, 100 rounds in the first session, 150 rounds in the second. I stripped and through-cleaned after the first session (did also some moderate cleaning before the 1st session). The basic problem is that the slide won't lock back 3 out of 4 times (roughly) after the last shot. Slide locks fine when I rack back the slide with an empty magazine in the gun.

Anything I can try/check on my end before I contact Beretta tech support? Could this be a "feature" of the 10 round limiter?

[_TomT_]

Have you tried changing your grip to make sure you're not pressing down the mag release? Also 10 round magazines or magazines that are not designed for the gun sometimes OEM ones can cause problems, even in Glocks.

[FalconLair]

might need to let the recoil spring break in some more

if it locks by hand racking i figure the problem has to lie in the spring action - spring may be really tight and not allowing the slide to fully go back after the last round

just my thoughts on it - if they're factory Beretta magazines and happening with all of them with a new Px4 you might consider hand racking it for a while to see if the spring loosens up some

and no, that's not a "feature" on any Px4 that im aware of

[golfrj]

Maybe try a different Brand of ammo for a while too, some ammo is lower powered than others (not moving the slide all the way rearward due to the new recoil spring).. JMHO

[saudadeii]

The suggestions above are good ones.

In addition, take the slide off. While carefully observing the slide stop, insert an empty magazine. Did it push the stop up? Now, carefully observe how much contact the follwer makes with the slide stop. Now grab the floor plate with the mag still inserted and wiggle the mag around. Observe and note any change in the contact area.

For a while, M&P mag followers didn’t have much contact area and the stop could slip off the ledge.

I too still have problems with not locking back on the last round occasionally. Turns out my thumb blocks the slide lock when I get too “grabby” with my thumbs forward grip. It mostly happens with pistols that have a long slide lock, like my SP2022, PPQ and even my M9A1. Especially if I shot a 1911 right before.

[CBR_rider]

Have you found the issue? If not, only things I can reiterate or add off the top of my head are:

Have you taken the magazines apart to clean them? Do you have any other magazines you could borrow to try and replicate the problem? Maybe let someone else shoot a few rounds in your magazines through the pistol to see if it is an operator error?


Lastly, Beretta USA appears to be having a 20% off sale on their website this week. Good time maybe to pick up a competition trigger group, steel trigger, D spring hammer spring, or maybe a few spare parts.

[eswrite]

Have you tried changing your grip to make sure you're not pressing down the mag release? Also 10 round magazines or magazines that are not designed for the gun sometimes OEM ones can cause problems, even in Glocks.

I'll check that, but wouldn't the mag fall if I were pressing the release? Or did you mean the slide release? Maybe I'm thumbing that enough to cause it to go forward.

The new/tough spring suggestion seems interesting, but a bit dangerous to feature in a new gun.

As for needing to clean the mags, even though they're brand new? All four? Worth a try if all else fails, I suppose.

[CBR_rider]

I'll check that, but wouldn't the mag fall if I were pressing the release? Or did you mean the slide release? Maybe I'm thumbing that enough to cause it to go forward.

The new/tough spring suggestion seems interesting, but a bit dangerous to feature in a new gun.

As for needing to clean the mags, even though they're brand new? All four? Worth a try if all else fails, I suppose.

[eswrite]

And of course bring different ammo to check that on your next range trip.

Thanks. I forgot to mention I shot two different brands of 9mm during that 2nd session, Winchester & Federal, IIRC.

[Deschoots]

I've had this issue with several handguns before. Every time it was caused by my thumb riding the slide stop. Try intentionally moving your strong hand thumb way out of the way of the slide/slide stop and see if it locks open.

[newbie1234]

https://www.brownells.co.uk/epages/UK.sf/en_GB/?ViewAction=Monitor&GUID=StoreUK-5B1DC313-2340-2EF4-45A7-AC1E050B2F80

My wild guess:
(1) The Slide Catch (Part #45) is push down by the Slide Stop Spring (Part #44).
(2) On the last round, Magazine Follower (part #63) pushes UP the Slide Catch (#45) to lock the slide back.

- If the Slide Stop Spring (#44) is too strong for Magazine Follower (#63) to push UP the Slide Catch (#45) then it won't lock back the slide.
or:
- After the fire, the blowback will push the slide backward, and then the recoil spring will push the slide forward. If the recoil spring to too strong then the slide is pushed forward too fast before the action (2) happen.

My fix (don't guaranty work, but it worth a try).
- Make sure the Slide Catch (#45) and Slide Stop Spring (#44) is not get stuck to the frame. Click up&down the Slide Catch (#45) couple hundred times to soften the Slide Stop Spring (#45), watch World Cup soccer while doing this.
- Rack the slide 500 hundred times to soften the recoil spring, watch World Cup soccer while doing this. How about shoot 500 rounds to breaking, same result.

Hope it will fix your problem .

[AregularGuy]

Man, Calguns is getting soft! The standard answer used to be Limp Wristing. I can't believe this thread has gotten this far without someone saying that. My vote is for new gun, stiff recoil spring, thumb riding slide stop. Maybe leave the action over night or for a couple of days to set the spring and watch the thumbs at next range trip. Oh, and hit the gym so you don't limp wrist it!

[eswrite]

I've had this issue with several handguns before. Every time it was caused by my thumb riding the slide stop. Try intentionally moving your strong hand thumb way out of the way of the slide/slide stop and see if it locks open.

Thanks. The more I think about it, the more this looks like primary root cause.

[eswrite]

I'm happy to report that I identified the issue. My shooting hand thumb was definitely resting on the slide release. Adjusting my grip so that my thumb is below the slide release at all times solved the problem. The slide now locks back after every last round in the magazine.

This left me with a less natural feeling grip, with my non-shooting hand (left) thumb not having as comfortable a placement. But, surprisingly, my accuracy improved -- nothing fantastic, as I am not all dialed in yet. But more practice and maybe some instruction (soon!) will get me there.

[CBR_rider]

Good work!

Like I mentioned earlier; if you want any of Beretta’s upgrades they are all on sale for Father’s Day it looks like.