Yes, you will have to weld on the extension and break, or a long break because you are adding length to the barrel to bring it to minimum legal length.ak'sr4me said:
(Exception 1) If your barrel extension is long enough to make the barrel legal, then the break would not have to be welded on.
Otherwise you would have to register this rifle as a "short barreled rifle" and pay the upropriate taxes.
Yours,
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