I had my 9mm P239 slide Cerakoted.

Now I can't get it back on the frame when the barrel and recoil assembly is in the slide.

Fits perfectly without a barrel.

Yes,I assume this is operator error, but I have zero issues dissembling and reassembling my other P239.

It feels like/ appears that the barrel ramp or lug is hitting the locking block. Check out the point I can't get past.

My first guess is that the barrel isn’t seating up properly in the slide. The thickness of the finish may be preventing that, and if the barrel doesn’t move up far enough, it would contact the locking insert.

^^^ my thoughts as well.

Have you tried to swap slides?
Making sure the problem follows the slide and not the frame.

The non-cerakote P239 is a .40S&W. Frames are the same, right?

I tried the cerakoted slide on the other frame with the same result.

Are these guns so tolerant? Supposedly 1 mil. "Cerakote is applied very thin, 1 to 2 mils, and will not affect the vast majority of
firearms. Extra care needs to be taken with tight tolerance custom actions,.."

The spray was applied by a firm that "coats upwards of 45,000 parts per year and has provided OEM Cerakote coatings" to numerous industries.

Two of the five barrel locking surfaces in SIG Classic line pistols are at the front and rear of the ejection port. The barrel hood should fit into the ejection port very tightly and precisely, and therefore anything that coats those locking surfaces might prevent the barrel from seating properly.

I would take a close look at how the barrels fit into the ejection ports of the two slides. If the one in the coated slide doesn’t move up into the ejection port as far, that’s no doubt the problem, and is no doubt due to the coating which could total 4 mils on both ends of the port even per the specs you cited.

Dagnabit that's got to be it. Thanks for the input.


Perhaps the barrel could be fitted?

Same thing happened to me after I had a terribly ugly 226 moly coated. It was the barrel locking tolerance that had changed. A little judicious filing and all was well.

quote:

Originally posted by Catalina:
The non-cerakote P239 is a .40S&W. Frames are the same, right?

I have been told by holster makers, Milt Sparks for instance, that the 9mm is slightly narrower then the .40.

It’s the height of the slide that is the difference between a 9 and a 40

I was going to suggest the locking block was not set right... but it sounds like you figured it out... can someone explain what the fix is?

and yes the two frames should be the same other than the difference in the internal sizing of the grip... 40/357 is wider than 9mm... I've switched slides and even internals between the two...

quote:

Originally posted by Blume9mm:
I was going to suggest the locking block was not set right... but it sounds like you figured it out... can someone explain what the fix is?

In what way do you believe that the locking insert could be “set” wrong and it still be possible to assemble the pistol?

If the coating on the locking surfaces of the ejection port is causing the problem, the fix would be to remove it from those surfaces. The contact points of the barrel should not be altered.