I have a semi-auto pistol in 5.56/.223 - Kel-Tec's PLR-16, it's my avatar here - who's barrel is 9" that I'm considering turning into a short barreled rifle. The main reason is I'd like to add a detachable shoulder stock for extra stability when shooting at longer distances (beyond 50 yds) but doing that would turn my pistol into a rifle as per the ATF. Beyond that, the gun would remain unchanged. Anyway, I am in the process of completing form 1 as required by the ATF for the necessary stamp and have a few questions that I hope those who have already been through the process of filling out the form may be able to answer. First: the area where you are required to supply your name and address (3b). The form says you only need to fill in your name and address but when you go to the ATF website and read the actual code, it also mentions your date of birth and location. Quote § 479.62 "The applicant must be identified on the Form 1 (Firearms) by name and address and,... if an individual, the identification must include the date and place of birth." Which is correct? Second: since I'm simply adding a shoulder stock to an already existing gun with a serial number and the other information required by law, do I still need to create a new serial number/ID or simply use the original number/info that is already on the gun? Finally, are there any particular areas that seem to cause problems/rejections for first time applicants that I should look out for? Any help from those with more experience with the ATF would be greatly appreciated!