SBR a stripped lower

[Clutch]

This thread has been helpful. Thank you. I have a lower which I intend to build as an SBR. I have a trust in place currently. Last night I was online filling out Form 1 to apply for my tax stamp. Not having built the rifle yet (since I don't have a stamp), I was a bit stumped on the questions of barrel length, overall length, caliber and purpose of build. I figured I would list 7.5" barrel knowing I'd likely be allowed to go longer but maybe not shorter. My lower is marked "multi" for caliber. While I plan to only configure for 5.56, I don't want to tie up my freedoms for down the road. So, now I know as long as I keep the declared barrel length of declared caliber to configure the rifle as declared, I can also still exercise the freedom to reconfigure however I like. Thanks again.

My intent for the build is personal collection and recreation within the law. Does anyone know if this individual intent needs to be listed differently when the stamp is being applied for by a trust, rather than an individual?

Finally, are the trust documents the only docs needed to attach to Form 1 or do I also need to submit any other docs such as the receipt or Maryland background form for the original purchase of the lower?

Thanks in advance for any input.

For the benefit of others, I found answers to my questions on the NFA FAQ thread and through links off of this page to other links, etc:

http://www.guntrustlawyer.com/form1.html

http://www.atf.gov/files/forms/download/atf-f-5320-1.pdf (see instructions)

http://www.guntrustlawyer.com/2010/03/batfe-engraving-requirements-f.html