The following originally appeared at the Defense Firearms Blog and is reprinted here with permission.
An SBR, or short barrel rifle is a category of firearm that is regulated by the National Firearms Act or NFA. Basically speaking it’s a rifle with a barrel shorter than 16″ or smaller than 26″ overall length. Another type of firearm that is similar is the Short Barrel Shotgun, or SBS, but we’ll focus on the SBR for now . . .
In order to legally own an SBR, one must first identify what the specifications of what the SBR will be. Specifically, you will need to actually identify what firearm you will turn into an SBR in order to register the serial number and the actual overall length of the firearm, make, model, caliber, etc. As an example, if you own an AR rifle (a rifle with a barrel 16″ or greater) and you want to shorten the barrel, you will need to have a serial number and decide how short you want the barrel.
For example, let’s say you want to change your barrel from 16″ to 10″, you will need to first measure the overall length. The overall length should include the size of the stock fully extended (for those that have adjustable stocks). Additionally, you will measure the length of the actual barrel tip and not include the flash hider, suppressor. The reason for this is that the flash suppressor is NOT considered a part of the barrel unless it is welded and pinned to the barrel.
Once you measure the entire length of the firearm, let’s say it’s 30″ for arguments sake, you will then subtract 6″ from that measurement (16″ minus 10″ equals 6″). Take away the 6″ measurement from 30″ and you have 24″ as your new “desired” length of what you will want when your SBR is legally assembled. Remember, you CANNOT legally assemble the SBR and take these measurements, and you CANNOT legally be in possession of all the materials to assemble an SBR until you have your approval from the BATFE, doing so is called constructive possession. In lieu of measuring the actual SBR, you will have to do the math above.
Once you have your serial number, make, model, caliber and measurements of your firearm you will fill out a Form 1 (http://www.atf.gov/forms/download/atf-f-5320-1.pdf). After filling out the Form 1, you will mail it along with a check for $200 to the BATFE and wait for you tax stamp approval.
Different states have different restrictions on owning an SBR. In other words, some states simply require you to get your fingerprints and get approval from your local Police Chief/Sheriff in order to complete the Form 1. Basically, the BATFE requires you get approval from your local law enforcement in order to get approval from them. I will blog about some of the different regulations per state as all states/counties have different laws.
Once you receive your tax stamp back from the BATFE, you are good to go (return times vary, contact the NFA Branch to get an estimated timeframe). Remember, ALWAYS have copies of your tax stamp paperwork with your SBR at all times, this will save you extreme amounts of trouble.
I hope this helps, if anyone has questions or see corrections/clarifications that can be made, please let me know. Also, as a disclaimer, this article is not legal advice. To get specific information on laws and regulations regarding NFA or firearms, please contact the BATFE or legal council.