This forum needs a sticky on this...
You can submit the Form 1 to ATF with the blue ATF fingerprint cards, pictures, $200, and certificate of compliance.
www.titleii.com/TitleII.com/Welcome.html You can get forms there. For two page forms like form 4 make damn sure they are printed front and back, if they are on two pages they WILL get sent back. YOu can get forms from the ATF as well.
Once you get the form back it is your baby. If you want the barrel cut by a gunsmith, take the gun to them and stay while they do it... Just remember that NFA guns are in a diffrent legal area than regular title 1 guns. You can't just drop off a SBS at the gunsmith and come back next week. You must fill out a form 5 if the gun is to be left with someone else for work. (I hear you can do other things but I don't know for sure.)