When it comes to air guns and the questions they generate for thier owners, I guess the best answer is, " It Depends". We are all plagued with the AG that 'won't do this' or' won't do that.' Or ' it does this' . What do I do? AGs are really complicated contraptions. And when you are tempted to think only one thing is causing the problem it is usually discovered to be several problems. So, I guess the best guess answer to any AG problem is...." It Depends". And that is not being a smart -ss.
Then begin the hunt.