I do not think that there is any point in speculating about what might or might not be accepted. The SSD guns are the most recent commercially manufactured ones that I know for a fact to have been approved. Have a good look at the mechanisms of these firearms. The FRT entries for both the 38 and 3008 mention that substitution of original parts will not result in full auto. Of course, for a 3008, that is irrelevant, because there are no original parts to substitute. Both these firearms have basic, uncomplicated trigger mechanisms.
Consider for a moment the SAS design, BATFE approved semi auto. The designer went to great lengths to make it closed bolt, hammer fired, floating firing pin, impossible to substitute an original bolt. Fine. But there is also the issue of intent. Substitute a newly made bolt, and guess what? All the design features go out the window.
Consider for a moment the SAS design, BATFE approved semi auto. The designer went to great lengths to make it closed bolt, hammer fired, floating firing pin, impossible to substitute an original bolt. Fine. But there is also the issue of intent. Substitute a newly made bolt, and guess what? All the design features go out the window.