Sounds like a bad seal or broken spring.It you 'break' the barrel open and it opens way up before starting to compress the spring it's a good sign it's broken. Clear the barrel and make sure there are no pellets jammed in it.If the guy is that bad about taking care of the gun, I suspect it's been dry fired.. maybe even many times.If it has set outside through some seasons, the seal may be dried out and cracked.... or just hard.If the spring is broken you most likely get it out without a spring compressor but you'll probably need one to get a new spring installed.
Yeah, he doesn't know how to fix it and neither do I. I told him I'd try to sell it as is.
Well. it cocks real easy and when you pull the trigger it makes a real faint burbing like noise and you can feel the gun kinda moving back and forth. I took the trigger guard off and pulled the action out of the stock but I have no idea what I am looking at. I've never worked on a springer I'm tempted to tell him it's toast and sell him my gamo 1250 Hunter.