Semiauto troubleshooting

[basilisk]

Was not sure if should post it into "shotguns" or "gunsmithing"...

I'm trying to troubleshoot the issue that's been plaguing my Winchester 140 semiauto - first round (manually chambered) never fails, but after the first shot, action is cycled without any problems, next round is chambered, but the pin is not "primed" so there is no "click" (or "bang") after a trigger pull.
Is it a common issue? Any help is appreciated! (It goes without saying that the gun is well-cleaned and all moving parts are well-lubricated).

If nothing helps, obviously, I'll take it to a gunsmith, but I was hoping it's something simple to fix.

[swifty]

... but the pin is not "primed" so there is no "click" (or "bang") after a trigger pull.

When you say "pin", do you mean firing pin? "Primed" is not a term generally associated with firearms, ammo yes, but not firearms. Do you mean cocked? If you do, then that is not related to the firing pin, the hammer would be cocked.

Check to see that the hammer is cocked when this malfunction occurs.

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Remove the Slide Support and look for a piece of loose shot.