I am doing to be getting a prommy barrel to go into a PDI chamber on a well mb05. My question is will a 500mm barrel fit in it without sticking out? Also if it doesn't than I can either get a 455mm 6.03 for 75, or a 420mm 6.03 for 60. I don't think the extra 35mm of barrel for 15 dollars is worth it. Help me out here.