I see all these things like belt fed uppers available that use registered M16 lowers. Is there anything stopping someone from making a backplate for something like an M1919 or M2HB that uses a different linkage inside a registered M16 lower (IE no modification is made to the lower, but the sear is located elsewhere)? Or if the weapon can fire without that piece it would have to be the registered part? What about an open bolt upper that is engaged by a modidied sear placed in a registered lower, a la an M240?
Mike
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Mike
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