It should lock back with the last round ejected. The slide lock, pushed up from the mag follower, may have been damaged or switched out when it was converted to .380 and then back.

 

No end of opportunities for mischief with two caliber conversions. Is the barrel solid in the frame boss?
Take the slide off, insert a mag, and see if the follower is engaging the slide stop/ejector.
Moon

 

Good afternoon,

Sorry about your difficulties. If you could post a photo of your pistol, with the slide removed, looking downward into the magazine well, this forum can help. I suspect you have the wrong slide lock/ejector installed.

Be well,
David

 

Thank you everybody for taking the time to reply and for your expert advise. I ordered a new ejector/slide stop for the 7.65mm cartridge and that solved the problem. The "gunsmith", and I use that term loosely, installed the wrong ejector/slide stop when he converted the pistol back to 7.65mm from 380 auto. The barrel is still nice and tight despite being converted from 7.65mm to 380 auto and back again. I can't wait to get out and see how it shoots but that will have to wait for cooler weather. The Arizona desert is just too damn hot in the summer. Again, thank you every body for your help.

 

I'd love to know the history of the double caliber swap. Glad you found a fix, and let us know how it runs.
Moon

 

Good afternoon,

Mr Moon, I think you would enjoy reading this post

http://www.waltherforums.com/forum/pp-tp-series/52329-ppks-9mmk-7-65-conversion.html

Be well,
David

 

keltec', thnx for the comeback; Mike's remarks in the link reflect my own; it was my impression that the barrel was more of a press fit in the frame boss. In any case, glad you were able to accomplish it successfully; I concur that 7.65 is the desirable caliber in these guns.
Moon