If the action has not been cycled in years, it is likely frozen. Hopefully it is just dried lube. Spray some Gun Scrubber into the ejection port. Let it sit for a little while. You may need to apply a little force. The charging handle is very small on these rifles. Getting a good grip is difficult. Use a block of 2X4 and smack it with a mallet. That usually will free it up. DO NOT USE A SLEDGE HAMMER. You can break stuff.
If it is rusted shut, It will take something like Kroil or 3 in 1 oil. Let it sit for a day or so.