Section 6.4 of the NFA
"The approval of the Form 1 application authorizes the applicant to make the firearm. The approval does not authorize the applicant to convey or ship the firearm to another person to manufacture the NFA firearm. If another person will manufacture the NFA firearm, the other person would be the maker and the application must be submitted by that person. Subsequent to the making, the firearm could then be transferred, subsequent to an approved Form 4 application, to the person who wanted the modification to be made.
If the applicant on the Form 1 lacks the skill, ability, and/or equipment to manufacture the NFA firearm, the applicant, after receipt of the approved Form 1, can have the firearm created or modified at a premises other than shown on the approved Form 1 as long as the creation or modification was done under the direct oversight of the applicant, thus having the applicant retain custody and control of the firearm. If the location is outside the applicant’s State and the firearm being made is a short barreled rifle, short barreled shotgun, destructive device, or an unserviceable machinegun which is being reactivated, the applicant will also need to request permission to transport the firearm interstate as required by 27 CFR 478.28."
If you are there it can simply be stated that you are making it. If the parts are in posession of someone other than a licensed NFA shop or the person on the Form 1. They could be in alot of trouble. I say it to protect the people helping you not to keep you from going to jail. Although I am sure they would frown upon you conspiring to not do it correctly.
I have heard of people making the tube, engraving it and what not then sending it to a 07 for "repair" IE baffles. you might as well avoid possible legalities and buy or hire them to do it all then.
