Re: Redoing your silencer to make a QD from a screw on
That's an interesting question. I think they can but there is some ruling regarding significant size change.
If the QD system can be installed without requiring replacement of the tube or imparting a significant size change it should be possible if the manufacturer will support it.
For instance, our M4-SD mount I don't believe could be retrofitted to an M4-SD TM [thread mount] on account of it adding 1" over a thread mount cap. The tube would not need to be altered, but I don't believe increased size of that amount is permitted.