I have an 870 Express HD with extended mag tube and want to convert it to the best I can to an actual real HD shotgun. After looking at this link it seems as though there is a bit of work that needs to be done. I was curious if you guys have any input on where I can find the parts I need. http://www.remingtonmilitary.com/articles/870ExpvsPol6-30-05.pdf Thanks for all your help in advance. Wanna kill these ads? We can help!