Did you clean the pistol of its preservative coatings, before trying it out? Preservatives are thick and tacky, and if there's some in the barrel's chamber, it'll grab onto a cartridge and not want to let go. Clean everything well with a solvent or "gun scrubber" spray, and try the process again.
Look at the ejected cartridge for bright, shiny streaks and scratch marks. Check to see if its bullet was pressed back and her into the case on its way into the chamber.
Lots of bright and shiny areas indicates a tight fit in the chamber. Either the chamber is too small, or the cartridge is too big. Check both with a micrometer caliper, to determine what to do.
Scratching may indicate a burr left in the chamber wall or its mouth. Strip the pistol and examine its barrel (inside) for tiny protrusions or rough areas.
If the bullet got pushed back, deeper into the cartridge, it may have bulged the case a little. Look for "dings" on the bullet's nose and shiny spots around the case.
Tell us what you find.