MPX PCC - mystery spring

[NervousEnergy]

Embarrassing topic, but I'm not used to unidentified parts coming out of my guns.  Have an MPX PCC (the 'gen 3' model) and a gen 2 for backup.  Took it apart today to clean it after yesterday's match as I've done many dozens of times, but a small spring came out of the lower when I separated the upper.  I've not paid a lot of attention to the lower with it's Timney trigger - I can't hardly tell any difference between it and the Hiperfire in my Gen 2.  I just swab out the old sear grease around the disconnector and hammer and put some new grease in.  I haven't removed the trigger or paid much attention to it, so if this spring came from there I don't know where it goes.  Can't find any exploded parts diagrams of the Timney or the MPX lower itself - my google-fu is failing me.  It looks way too big to be the Timney disconnector spring, and I have no idea how it would have gotten out of there intact.  Spring doesn't look broken.  Picture attached with 9mm round for sizing.  Part of the safety?  Safety seems to work fine.  

 

Dry fire function check is perfect, but there's no way I'm taking this to a match with an unidentified spring missing.  I don't even want to fire it at a range without knowing what it is.  Once again, embarrassing question, but does anyone have a clue where this goes?  

[smoker 01]

It looks like the firing pin spring to me

Gr

Edited February 2, 2020 by smoker 01

[NervousEnergy]

Nope, firing pin spring is larger than this one and is accounted for.  

[Rolex]

extractor spring 

[ck1]

Dust-cover detent?

[Chillywig]

Maybe?

 

[Silverscooby27]

Aftec extractor spring?

[inertia]

6 hours ago, Silverscooby27 said:

Aftec extractor spring?

In a MPX?

[Silverscooby27]

4 hours ago, inertia said:

In a MPX?

Exactly. Maybe it’s something extra that fell in there since it seems like everything else is functional without it.

[NervousEnergy]

Not the extractor - that spring is tiny compared to this (less than half the size) and it's still in place.  I've broken the extractor spring twice on my gen 2 - they seem to die every 5000 - 6000 rounds, and the hiperfire disconnector dies around 8000.  This Gen 3 has maybe 4000 on it.  It could be the disconnector, but the trigger is resetting fine in dry fire.  The one time the disconnector spring broke on the gen 2 it broke in half (Eclipse), but stayed in the trigger housing.

 

I was going to take it to the match tomorrow to test it but shoot the backup Gen 2, but it's cancelled due to rain.  That will give me time to remove the Timney and see if most of the disconnector managed to escape (can't see it directly due to the hammer bridge).  If that's not it I don't know where else to look - perhaps take apart the safety and see if the detent spring is missing.  Safety feels exactly the same, though.  

 

Really annoying that I can't seem to find a full exploded view of every part in the MPX Gen 3.  Is there such a thing?  The only pictures I can find of the Timney is the gold version, which isn't exactly the same as this black one that come stock.  

 

I'll check the bolt catch spring, but the bolt catch lever seems to have exactly the same tension on it.  

 

Thanks for the ideas!  I'm used to a few parts left over after major car work, but not guns.  

Edited February 9, 2020 by NervousEnergy

[Rich406]

On 2/8/2020 at 10:33 PM, NervousEnergy said:

Not the extractor - that spring is tiny compared to this (less than half the size) and it's still in place.  I've broken the extractor spring twice on my gen 2 - they seem to die every 5000 - 6000 rounds, and the hiperfire disconnector dies around 8000.  This Gen 3 has maybe 4000 on it.  It could be the disconnector, but the trigger is resetting fine in dry fire.  The one time the disconnector spring broke on the gen 2 it broke in half (Eclipse), but stayed in the trigger housing.

 

I was going to take it to the match tomorrow to test it but shoot the backup Gen 2, but it's cancelled due to rain.  That will give me time to remove the Timney and see if most of the disconnector managed to escape (can't see it directly due to the hammer bridge).  If that's not it I don't know where else to look - perhaps take apart the safety and see if the detent spring is missing.  Safety feels exactly the same, though.  

 

Really annoying that I can't seem to find a full exploded view of every part in the MPX Gen 3.  Is there such a thing?  The only pictures I can find of the Timney is the gold version, which isn't exactly the same as this black one that come stock.  

 

I'll check the bolt catch spring, but the bolt catch lever seems to have exactly the same tension on it.  

 

Thanks for the ideas!  I'm used to a few parts left over after major car work, but not guns.  

did you ever figure this out?