I have a Sig P239 in a holster sewed into the canvas shoulder bag I carry when walking my dogs... have not shot the pistol in well over a year, it is always in this bag along with the poop bags and a few other items. Took it with me to the beach this past month and the bag hung on the screen porch facing the ocean and so two days ago I decided it might be a good idea to clean and oil the pistol.
I did this and then when I put it back together it would not trip the hammer in single action as in cocking it by racking the slide. The hammer would work in double action but did not seem right.... I could not figure it out... took the grip off and messed with it for a while, finally got another P239 and looked at it... after 30 minutes or so gave it a rest... came back yesterday morning and spent another 20-30 minutes trying to diagnose the problem... then I put the slide from the other pistol on and discovered it worked fine but in switching the slide on the 'dog bag pistol' was the problem... still could not figure it out... finally yesterday afternoon I started examining the two slides again... and finally saw the difference and the issue... I never knew what this little indented disc was in the back underside of the slide that sits beside the firing pin... in looking at the pistol's diagram it is called the safety lock and I presume it keeps the firing pin from moving forward unless the trigger is pulled. It seems to have some little spring above it that allows it to move up and down and the one on the dog bag pistol was seized up and would not move. I sprayed it and sprayed it and finally took a right angle pick tool and was able to get it to move and with a lot of WD40 and CLP I finally flushed it out and got it free..... In spending years cleaning and lubing these pistols I never have thought about this little part.
My point is the saving grace was having two of the same to compare ...(I actually have more than two).
I did this and then when I put it back together it would not trip the hammer in single action as in cocking it by racking the slide. The hammer would work in double action but did not seem right.... I could not figure it out... took the grip off and messed with it for a while, finally got another P239 and looked at it... after 30 minutes or so gave it a rest... came back yesterday morning and spent another 20-30 minutes trying to diagnose the problem... then I put the slide from the other pistol on and discovered it worked fine but in switching the slide on the 'dog bag pistol' was the problem... still could not figure it out... finally yesterday afternoon I started examining the two slides again... and finally saw the difference and the issue... I never knew what this little indented disc was in the back underside of the slide that sits beside the firing pin... in looking at the pistol's diagram it is called the safety lock and I presume it keeps the firing pin from moving forward unless the trigger is pulled. It seems to have some little spring above it that allows it to move up and down and the one on the dog bag pistol was seized up and would not move. I sprayed it and sprayed it and finally took a right angle pick tool and was able to get it to move and with a lot of WD40 and CLP I finally flushed it out and got it free..... In spending years cleaning and lubing these pistols I never have thought about this little part.
My point is the saving grace was having two of the same to compare ...(I actually have more than two).