Hey there,
Recently picked up a used Winchester 2400 too; couldn't find very much info anywhere. Finally found a couple web references indicating the 2400 was the same basically as the Winchester 1400 - the 2400 was just the version/model no given to the model 1400 when manufactured in Canada (don't know for sure how true the manufacturing info is).
Anyway, checked youtube for info on the model 1400 - there's a couple of really detailed disassembly & reassembly videos available - just look for keywords "Winchester 1400 disassembly". From what you described in your first couple posts, it sounds like you haven't removed the split ring retainers inside the fore grip (just a guess) - accessible after you take off the mag cap. From the video, if your gun was as dirty as you say, they might not be easy to move. Once they come out, the fore grip comes off easy & you can access/compress the spring & get the barrel off. Great video - worked for me (did seem odd following a computer video while cleaning my shotgun, but if it helps me do a detailed field strip, OK). Hope this helps . . .
w0160941