I suspect the "tab guide" you refer to may be the part of the firing pin/striker that is engaged by the sear - if so, it won't cock - therefore wont fire (or pass the dowel test).
As I recall, you get a clicking sound when you pull the trigger on an uncocked pistol of this type, which may fool you into thinking the mechanism is "firing".
As I recall, you get a clicking sound when you pull the trigger on an uncocked pistol of this type, which may fool you into thinking the mechanism is "firing".
