So, this may or may not be relevant to this discussion, but I have had personal experience with two rimfire firearms that have had similar problems. One was a 1950's vintage S&W 22LR revolver that was manufactured with notoriously tight chambers and the other was a BSA Model 12 Martini with a factory-reamed match chamber. The revolver would not fully seat any CCI or larger diameter cased ammo, only Federal or similar/smaller diameter cased ammo. Fortunately it shoots lights-out with cheap Federal blue-box HV and copper-washed bulk HV and ejects both flawlessly. My first few tries at hand-seating the larger rounds ended up with me mechanically persuading them to exit their respective chambers. The Martini chamber was large enough to snugly accept CCI and similar diameter cased ammo, but each round needed to be "cammed" into the chamber with generous pressure from the lever. The very positive force exerted by the Martini extractor/ejector never failed to kick them out, but it was very obvious that it was reluctantly. Again, fortuitously, that rifle shot it's tightest groups with el cheapo Federal blue box HV. Maybe a case of incompatible ammo?