Without having owned the shotgun you describe or actually seeing it, I am certain that you should be able to take it apart. I have a Remington 870 supermag and taking the forend/pump is as simple as unscrewing the retaining screw cap at the end of the magazine tube and sliding off. I am not sure if the same thing will work for you, but give your Win a good look over, note how it is assembled and try to disassemble, while keeping reassembly in mind/how parts go together. You could also do an internet search for how to assemble/disassemble by your brand and model as well. Good luck.