I'm working on my first SBR and have a question. I have a down payment on the components from Rainier Arms in WA.

I previously ordered an upper then lower from them. The upper was a 14.5 with a pinned (non-NFA) FS. I've been using this carbine at work as a personally owned patrol rifle.

I decided I want a short upper. Rainier sold me the lower and 14.5 upper. Rainier is assembling a 7.5 inch Daniel Defense/Noveske Diplomat creation for me as parts come in. Once it is assembled, they will ship it. I understand I cannot assemble the lower and upper until I get my Form 1 back.

My question is, who is making the SBR? Is Rainier the manufacturer, since they sold me the lower which I am using as the SBR host? Or am I the maker since I will be putting the upper and lower together by snapping two pins in place?

I ask because I want to get it submitted asap. I know I may need it engraved with something as well.

I'm just looking for Cliff's notes on it. Not a link to the ATF handbook.

Thanks!