In order to build an SBR with an existing lower, the owner must apply for a SBR tax stamp using ATF Form 1, registering the SBR under a trust or as an individual.
Trust is a legal entity and as such can legally own assets. One of the most popular methods for getting a NFA stamp is using a trust for a couple reasons. Depending on the trust you select and it's legal language, the process of inheritance of NFA items can be considerably easier. A trust can provide the ability for the control to move to another person without actual ownership the of the item changing. Another benefit if you select a trust with the ability to add/remove co-trustees is you can allow other individuals to posses the same NFA items without you present.
Individual just as it sounds means you file the for the stamp in your own name and you are the sole owner of said NFA item. This also means you as the individual approved for the stamp are the only own that can solely be in possession. Others can use your NFA items but only if you are present. In the event you pass away, and a valid will is in place, your heir can request a tax exempt transfer of the NFA item into their possession.
The following information will be required to complete the Form 1:
- Original Manufacturer (as printed on the firearm)
- Type of Firearm (Short Barreled Rifle)
- Caliber (base number only, i.e. .300, 308, .223, etc)
- Model (as priced on the firearm from original manufacturer)
- Length of barrel (as measured from the bolt face to muzzle tip)
- Length overall (measure with stock fully extended and no removable muzzle device installed to the muzzle tip)
- Serial number (as priced on the firearm from original manufacturer)
- State why you intend to make a firearm ("for all lawful purposes")
The Form 1 can be filed electronically or on paper. Electronic (or eForm/eFile) filing has some distinct advantages. When the form is submitted online, you are charged immediately and can pay via credit card. Approvals via electronic are slightly faster, especially with delivery of your approved paperwork. In the case of electronic you will immediately get an e-mail with the Form 1 stamp attached once approved. Paper file is still very popular. One distinct advantage of paper file is the ability to make some corrections to the form after review by the examiner. Whereas with electronic any error results in an immediate disapproved and you start over.
While awaiting approval, the firearm, still in title 1 configuration, can legally remain in your possession. The Form 1 is a request for permission to manufacture an SBR.
Upon approval and receipt of the SBR tax stamp, firearms registered under a trust will require an updated Schedule A, listing the new SBR as an asset (Original Manufacturer, Country of Origin, Model Number, and Serial Number). The trust info will needed to be engraved on your firearm as new the manufacturer along with city and state where the trust is located (per your trust document). The engraving can be in plastic or metal along as it is at least .003" min depth and 1/16" min print size. The complete trust name along with the city and state the trust is located must be included in the engraving. Trust info can be engraved on the frame, receiver, or barrel. The receiver is the most popular location because any changes to the other components would not require the engraving to be repeated.
Finally you can legally manufacturer your new SBR.
Changing calibers and/or barrel length after receiving tax stamp
Your Form 1 was approved for a specific caliber, overall length, and barrel length. However you are allowed to "temporarily" change the upper length or caliber but only if you maintain the original upper and ability switch back afterward. If you sell the upper and switch permanently to a different upper then you would need to send a notification to the ATF letting them know of the official change. You do not pay the stamp or go through the Form 1 process again, just a notification.
Transporting SBR (in/out of state)
You are free to travel with your SBR within the same state as you reside. When traveling out of state first and foremost understand the laws of the state you are traveling. If local state residents can not posses a SBR then you as a visitor can not either. Before traveling across state lines with your SBR you need to submit a Form 5320.20 to the ATF and wait for approval. This form does not cost anything, but takes 4-8 weeks to get back approved so plan accordingly. Another option is temporally return the firearm to the title I configuration and then you can freely travel across state lines (again know local state laws for title 1 firearms).