I inherited my grandpa's 870 a few years ago, and due to a busy college schedule, I haven't had time to even get it out of the gun cabinet. It needs a good cleaning, so I started to get it apart, but can't get the forend free.
Here's the gun

When I press down on the little metal clip on the inside of the action, it releases about a centimeter and hangs up. Any ideas?
It's pretty old. Here's the code on the barrel.
