SBR procedure overview?

[Hoser]

How come? And what do you put down then if the lower says Multi?

If you put down 5.56 or .223Rem, can you change out the upper later to have, say, a 300AAC Blackout upper?

Changing calibers or barrel lengths is not a permanent change.

Just pick one and go with it.

I have a form 4 from long ago where I listed MULTI and it went through. Now days they kick them back.

[BuffCyclist]

Ah, gotcha, so it doesn't matter what you put unless you want it kicked back. Thanks!

[Great-Kazoo]

How come? And what do you put down then if the lower says Multi?

If you put down 5.56 or .223Rem, can you change out the upper later to have, say, a 300AAC Blackout upper?

Ah, gotcha, so it doesn't matter what you put unless you want it kicked back. Thanks!

yes and maybe. If the lower is anything other than a dedicated 9, 45, 22lr etc. I go with 5.56 . if you have a dedicated DDLES then you put 9mm.

You may temporarily alter the caliber provided you can restore it to the original configuration (meaning you can put a 22 conversion on your 5.56 SBR for a cheap range trip), but you should still keep the 5.56 upper.

[J]

To expand... you can temporarily change the length/caliber at will. So keep the other upper, and you are fine.

However, if you ever want to rebuild your primary upper in a different length or caliber, it is just mailing to the ATF to inform them that the change has happened. There is no approval, or waiting. Just send it in and make your change, so it isn't as big of a deal as some make it out to be.

[RCCrawler]

However, if you ever want to rebuild your primary upper in a different length or caliber, it is just mailing to the ATF to inform them that the change has happened. There is no approval, or waiting. Just send it in and make your change, so it isn't as big of a deal as some make it out to be.

Hmm, I may have to look into that. I have an SBR I built as an 8"er that I'm really kicking my self I didn't build a little shorter. It'd be simple to just take it to Bert and have him re cut and thread the barrel, but I thought I'd have to resubmit.

[Great-Kazoo]

Hmm, I may have to look into that. I have an SBR I built as an 8"er that I'm really kicking my self I didn't build a little shorter. It'd be simple to just take it to Bert and have him re cut and thread the barrel, but I thought I'd have to resubmit.

I put all my SBR's as 7" bbls AND 5.56 This gives you leeway ( BBL and OAL )if you decided to drop a 22 or 9mm upper on. YMMV

[RCCrawler]

I put all my SBR's as 7" bbls AND 5.56 This gives you leeway ( BBL and OAL )if you decided to drop a 22 or 9mm upper on. YMMV

That wouldn't have worked in either of my examples.

On one of mine it's built on a 15-22, I cut it to 8 not thinking that it takes less than 5.5" to keep most ammo subsonic, so I'd now like to cut 2.5" off of it. My understanding is I can go longer with no problem, but shorter and I have to fill out paperwork even if I keep this current upper on hand and buy another one.

Another one of mine is built on a DDLES dedicated 9mm lower with a 3" barrel.

[Circuits]

My understanding is I can go longer with no problem, but shorter and I have to fill out paperwork even if I keep this current upper on hand and buy another one.

No. You can go shorter if you want.

[Lurch]

I put all my SBR's as 7" bbls AND 5.56 This gives you leeway ( BBL and OAL )if you decided to drop a 22 or 9mm upper on. YMMV

Its my understanding you have to be able to bring it to the original Form 1 filing. So what will happen in the off chance the ATF comes a knocking?

[Great-Kazoo]

Its my understanding you have to be able to bring it to the original Form 1 filing. So what will happen in the off chance the ATF comes a knocking?

Not a thing. ALL our AR SBR's wear their NFA stamp uppers. The other caliber uppers sit in a designated SBR rifle case. They can ask at the range, or in a vehicle (with warrant) nothing to elicit future inspection.

Other caliber uppers are fun / range toys. The 5.56 / 223 ones are kept intact, as they are PD, HD, all around go to guns.