If I do the math correctly it looks like the Geco ammunition you are using runs about 870 FPS at the muzzle. In my opinion this is a bit faster than "normal" .38 Special W/C ammunition runs here. The last box of new Federal W/C ammunition ammo I chrono'd was 755 FPS out of my M52. So the Geco ammo is definitely faster, perhaps too fast. You do say you get some cases that eject and some that don't.
This begs the question of the recoil spring being up to snuff for the ammunition you are using. Have you installed a new recoil spring in this pistol lately? Are you using a recoil buffer of any sort? Can you take a picture of the ejector as it is installed in your pistol? I know, lots of questions, but if the pistol works sometimes it may not be a bad ejector right off the bat. It could be something else at fault. I like to examine and or replace the easiest parts first, then go deeper.
Just for the record, I set my reloads at about 730 to 750 FPS for my M52's. My reloads are more than accurate for me and the barrel cleans up quickly with little lead fouling and the pistols run like a clock with these loads. I am not saying the recoil spring is bad or defective, but they should be routinely replaced. I know you have replaced the extractor and this is another area that needs some amount of examination to make sure the new one is fitted properly, but this is another discussion for later if necessary.
It can be a source of argument, but I use almost no grease on my semi-auto pistols except on the face of the hammer. Slide rails and such get high quality oil with good holding abilities. I like Lucas firearms oil, but that is my preference. Grease can have a way of slowing things down when you don't want that to happen so go easy with the grease if you use it. I would feel differently if you were shooting an M1 Garand, but the Model 52 is a finely assembled pistol with close tolerances.
Good luck with your Model 52.
Rick H.
