I am the person that started this thread 4 years ago. Here are similer but different Questions;
Are Atlas HO U36C shells, red box, black box, master, compatible with all the U36C red, black, master, Frames? Also, are all Atlas U30C somethings, compatible? For example, can I plop a Red Box U36C shell on a master series U33C frame, and so on? Thanks, JB