ACR SBR

[MattR]

I'm thinking about doing an SBR with my ACR, the rifle now is marked "multi" for caliber. Will I need to list each different potential caliber on the form or is "multi" going to be ok? I know my AR I had to list each but it was marked 5.56. I'm about positive that any caliber change will have to be done myself since BM has no support for this rifle and really 300 blackout would be about it. I would love a 9mm or 40/10mm conversion too but that is probably not feasible in the ACR.

[lc_nab]

You need to state a specific caliber on the form, They will not take multi caliber.

However once registered and approved by ATF, you can change the caliber.

[brutal]

You need to state a specific caliber on the form, They will not take multi caliber.

However once registered and approved by ATF, you can change the caliber.

This.

My SBR AR lower is marked multi. I submitted the initial build caliber as 5.56 and the initial build length as 7.5". My research shows BATFE no longer approves "multi" or multiple calibers listed on a Form 1. One and done.

Any other caliber or length is considered temporary. You only have to notify via letter of a permanent change.

[Great-Kazoo]

Put it down as 5.56 and leave it. No reason to complicate any paperwork.

[Hound]

Put it down as 5.56 and leave it. No reason to complicate any paperwork.

This is what I have done on mine.

[Hoser]

About 5-6 years ago my form 4 was approved when I listed the caliber as multi. But, times have changed.

[MattR]

That's kind of what I thought, just wanted to be sure before I sent it off and waited a year.

[ray1970]

Won't the receiver have to be engraved somehow? Just curious how that would be done on the ACR.

(Forgive me if I'm wrong. All this NFA stuff is still Greek to me.)

[Great-Kazoo]

Won't the receiver have to be engraved somehow? Just curious how that would be done on the ACR.

(Forgive me if I'm wrong. All this NFA stuff is still Greek to me.)

Colorado gun writes can do it. They did a nice job on the spouses cav-arms lower.