[glenwolde]

On the misfires, it seems like the slide isn't completely in battery? This would cause the round to be a bit "low" for the firing pin. Try slapping the the slide to be sure it's fully seated for every round and see if you can get through a box.

 

[glenwolde]

Try putting a dot on the rim with a Sharpie, and load them all "dot up". It might be helpful to know if the off-center strike is high-low-left- or right.

It occurs to me this could all be the extractor being too tight, not letting the case slip all the way in sometimes, and holding it too well when it hits the ejector. Do try some other brand of ammo.

I'd be tempted to remove the extractor and clean up any sharp edges and see if there's any of that grease in the pivot/spring area.

 

[glenwolde]

glenwolde, that makes a lot of sense. I wish I knew how these things work, but I think I understand what you're saying. I was wondering about the extractor. It seemed a little stiff and I soaked and lubed that area, but I did not remove it. I believe the PT138 has a pin that runs vertically, that the extractor pivots on. I'm guessing I can punch that pin out and release the extractor, but I have no idea where the spring may appear (zinging across the room or whatever). I will have to see if I can find some specific video or diagram so I don't end up making a bad situation worse. The way that old grease was in there, I could sure see it messing with the extractor mechanism.

Thanks for that fantastic suggestion!

There should be a drawing somewhere. I removed one from a PT609 once and it wasn't difficult. They are similar guns. I drove the pin out from the inside-out. There's the pin it pivots on and then there's a spring and plunger that pushes on the opposite end from the claw. There was also a loaded chamber indicator blade in the same assembly in the 609.

 

[glenwolde]

An update.

I finally made it back to the range today. I actually ran over 50 rounds through the gun, without ever failing to eject a round. After another thorough cleaning, this time taking the extractor out and cleaning that area, this time it didn't fail. Interestingly, after all that cleaning, it still wouldn't extract a snap cap, so I didn't hold out much hope.

Here's what was different:
I never loaded more than 7 rounds in each magazine (in the past, I'd loaded them up, 10 rounds).
I removed the extractor and cleaned/lubed the area (in the past, I'd never removed the extractor).
I used Winchester JHP, Blazer, and Herter ammunition (in the past, I was using Remington UMC).

I did mark some shells at twelve o'clock, anticipating the same problem. However, as you can see by this picture, it looks like it is striking on target.

View attachment 424497

Is it going to fail again? Who knows, but at least it worked this time where it hadn't before. Next time, I'll load up the magazines and see if that changes things. Then I'll try some Remington again and see if that changes things. If not, I guess it must be the extractor removal and cleaning.

Thanks to everyone who gave advice.

Sounds like a WIN to me....