If problem is the same with 2 barrels, the slide is clearly not having enough return power to strip a round, fully chamber it and close the slide.
So many things could cause that, friction in the slide, friction in the hammer reset, installed buffer, recoil spring with closed end to rear...
Also, the inside wire end of the muzzle end MUST be checked for sharp point. I got one which tore up a guide rod. For a pistol which is on the edge of having enough recoil energy, using any of that energy to scratch the rod will cause failures. I have a couple used guide rods thanks to...
Since the rounds drop in the chamber, I'd skip the cleaning suggestions. I found a problem with my ejector/slide stop by cycling rounds by hand and seeing that they did not eject cleanly. Having the ejector replaced has made the gun dependable with any ammo.
Cycle the gun by hand to see what...