Midnight. The $200 tax you pay is one time only on that particular NFA item. The only time another tax is needed is if you buy another one or transfer yours to someone else. It CAN be on your gun in your house. The only rule to watch is according to the rules you can be the only one to have access to it. ATF isn't gonna just come in your house for the hell of it. Their are thousands of owners with registered NFA items that will never here from NFA or ATF again.
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