It is a best-grade Greener (note the gold crown on toplever) built on the Self-Acting Ejector patent of 1881 (see ejectorwork in front lump of barrel). I'd bet there is a problem with the cocking and ejecting work there and if so therein lies the problem. Good system if not bodged but if that is the problem it will be difficult and expensive to fix. Levers for cocking and ejecting are small and demand utmost precision in fitting and new ones will have to be hand-made and fitted and properly regulated by someone who knows what they are doing -- like Greeners.
