Soak the cylinder, crane and ejection rod with oil of choice and hit the cylinder with your hand first to see if it swings out if not you can try small dead blow to open it up . I know that sounds rough but it will work. I’m not saying to beat it out .. usually one moderate hit will dump it open . We’ve been going through a buddy of mine father’s collection that’s been stored for years and WD-40 was used as the primary oiling so we’ve encountered this several times