Hi Thanks for the tip but It didn't work , I did email Remington and this was there reply.
Response Via Email (Danny)12/27/2012 11:14 AM
It is locked against the shell latches. Push it back into the receiver slightly and hold the shell latch down while pulling it forward. It should slide past the shell latch while doing this. Getting it back together will be even more tricky. You have to work with both shell latches instead of just one. If you can clean it fairly well while it is still in the receiver, you may want to just leave it in for simplicity sake.
Customer By Email (Cha Vang)12/25/2012 02:13 PM
Hi I need help on my Remington 870 20 gauge Express. While disassembling my 870 for cleaning , after taking off the barrel I couldn't get the pump and the bolt out. It seems to be stuck! I press the shell release and tried to pulled it out but it's not working. I got the trigger out but the bolt is still stuck. How do i get it out?