I have a Webley mark3 underlever which I have had since I was a lad which is a long time ,just recently on cocking and firing it lets out what can only be described as a loud burp, on re-cocking it usually fires no problem ,then twenty or so shots later it does it again.
I have stripped and cleaned everything applying a little silicone grease where needed, but this has not cured the problem, everything inside looks in fine condition but it has not cured things at all, any advice please greatly appreciated.