I have a speedfeed IV (full stock w/pistol grip) on my 500. I too had a black warrior stock that interfered with the manual release, piece of junk. The speed feed does not interfere the manual release. There is one minor problem, the stock must be removed or atleast loosened up to remove the trigger assembly. I guess I could remove some material from the stock but I remove the stock and take the whole thing apart to clean anyway. Here is where you can get a look at the kinds speed feed offer:
http://www.arizonagunrunners.com/Pro...speedfeed.html
curious