View Full Version : Rules for swapping uppers on AR-15 SBR?

ratas calientes
October 11, 2015, 20:24
I have two AR-15 SBRs: a 300 BLK and a .22LR. What are the rules for swapping uppers, changing calibers, etc.?

October 12, 2015, 06:17
Technically you can put whatever you want on the upper. The registered part
is the Lower. The way I read it, it would probably depend on whether it's a Form 1 or a Form 4. I did a Form 1 and it asks you to list the overall length and caliber. A Form 4 is generally something made by a mfr'r either a complete rifle or a Complete Lower. As far as I know you are free to change
uppers but have the one it was registered with available. If you have a 16" upper on it is NOT an SBR.

October 12, 2015, 10:58
IIRC, temporary changes to the OAL, caliber, and such are fine, but they really want it back in 'as registered' configuration at the end of the day.

October 12, 2015, 11:26
This is a really vague area. Yes, when listed for register or transfer, both the caliber and the barrel/overall length are listed. But some guns switch easily between barrel length and caliber. ATF used to accept "multi" but no longer does.

This page and the linked .pdf cover it well.


In short, yes, you can change caliber and barrel length.

October 12, 2015, 22:05
Is it possible/legal to go shorter?

example...have a registered sbr 10.5" .223. Could I swap it with at 8" 300BO upper? If only temporary?

October 13, 2015, 06:14
Is it possible/legal to go shorter?

example...have a registered sbr 10.5" .223. Could I swap it with at 8" 300BO upper? If only temporary?


ratas calientes
October 15, 2015, 11:32
Thanks for the info. First SBR was a Form 1; a .300 blk with 8.5" barrel. Just got back my second Form 1 stamp, for a .22LR SBR with a 4.5" barrel. What was interesting was that I had the Form 1 for the .22 returned for corrections. I had filled it out the form for the second SBR exactly as I did the first. But this second examiner wanted them filled out differently. Interesting. I can post more details if anyone is interested. (I am posting from work now and I don't have the paperwork available.)

October 15, 2015, 18:40
Yes, details please - as usual makes my faith in the system dimmer.

ratas calientes
October 18, 2015, 23:01
Here are the details. I hope this makes sense. (I really hate forms . . . )

This is a portion of my first Form 1. 300 blackout SBR build. This went through fine and I received the tax stamp end of last year. Serial number changed to XXXXXX for a little privacy. Looks like I left my phone number there . . . oh well . . . I am in the book and easy to look up.

http://i1003.photobucket.com/albums/af157/ratas_calientes/SBR%20Forms/1%20300%20blk%20SBR%20Form%201.png (http://s1003.photobucket.com/user/ratas_calientes/media/SBR%20Forms/1%20300%20blk%20SBR%20Form%201.png.html)

So I figured this spring I would file for another SBR. This one a .22LR build. So I filled it out like the 300 blk build above:

http://i1003.photobucket.com/albums/af157/ratas_calientes/SBR%20Forms/2%2022%20SBR%20first%20Form%201.png (http://s1003.photobucket.com/user/ratas_calientes/media/SBR%20Forms/2%2022%20SBR%20first%20Form%201.png.html)

About one month ago I received this letter from ATF. They wanted some changes. Note how they wanted 4.d "model" to match what was on the receiver. I guesa this "model" is not an AR-15, but as marked a "LAR-15". And they wanted the markings that I would add . . . trust name . . . listed in 4h.

http://i1003.photobucket.com/albums/af157/ratas_calientes/SBR%20Forms/3%20SBR%20corrections%20001.png (http://s1003.photobucket.com/user/ratas_calientes/media/SBR%20Forms/3%20SBR%20corrections%20001.png.html)

I updated and resent this new Form 1, changes as shown. Interesting.

http://i1003.photobucket.com/albums/af157/ratas_calientes/SBR%20Forms/4%2022%20SBR%20second%20Form%201.png (http://s1003.photobucket.com/user/ratas_calientes/media/SBR%20Forms/4%2022%20SBR%20second%20Form%201.png.html)

October 19, 2015, 09:21
Gotcha - thanks for the info

ratas calientes
October 19, 2015, 11:18
Gotcha - thanks for the info
You are most welcome.