Just receiving your rifle from a gunsmith (or anyone else) is an activating event, according the FSA, whether or not the gunsmith had it for 30 days or a lesser time. However, in practice it is an event they cannot trace.
(When they say the rifle has to be transferred to the Gunsmith's dealer license after 30 days (or anybody you may have lent your rifle to) they are talking in the context of both parties being registered already.)
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