IF you made the purchase from a licensed individual, and had it transferred to your license, you log it out to your personal collection in your A&D book- no 4473. However, if you then sell that gun in the next year, it is treated differently. C&P from BATFE:
Q: May a licensee who has firearms in his or her private collection sell any of these firearms without making firearms record entries?
A licensee may sell a firearm from his or her personal collection, subject only to the restrictions on firearm sales by unlicensed persons, provided the firearm was entered in the licenseeâs bound book and then transferred to the licenseeâs private collection at least 1 year prior to the sale. When the personal firearm is sold, the sale must be recorded in a bound book for dispositions of personal firearms, but no ATF Form 4473 is required.
[27 CFR 478.125a]
If you bought from a licensed person, but do NOT have it transferred to your license (you did the 4473 thing with the seller) then you do nothing- EXCEPT- if it is on your licensed premises, tag the gun as "personal property, not for sale". Avoid having personal arms mixed in physically with stock for sale. Bad ju-ju on an audit.