SBR AR 15 to be or not to be

[PORSCHE928S4]

When you SBR a AR is the upper or lower serialized ? If it is the upper must you register a specific caliber or can you change the caliber of your SBR-AR ? If the lower is the registered part can you change uppers to your hearts desire ?

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[aholley777]

its a free world and no one is your boss, your weapon.

 

[PORSCHE928S4]

its a free world and no one is your boss, your weapon.

I like the way you think and is true but legally ?

 

[aholley777]

I like the way you think and is true but legally ?

unless you are doing something very illegal, the government doesnt give a hoot about me or you. Last part isnt my concern cause its all legal.

 

[solv3nt]

Lower is serialized.

 

[PORSCHE928S4]

Lower is serialized.

Do you know once legally registered you can run whatever caliber upper you desire ?

 

[VinnieBoomBah]

The lower is the registered part and you can change the upper and cliber to your hearts' content. in theory you need to have available an upper in the caliber you listed on the form 1, but I have been told by a couple SOT's and other folks that would know you have to be VERY deep in trouble for lots of other stuff anyone to acutely care about that detail

 

[solv3nt]

Do you know once legally registered you can run whatever caliber upper you desire ?

My understanding is that once you have it. You are free to swap it out, but I'd keep the original upper stuff to be able to swap it. Otherwise, I Believe you have to let the AFT know about the difference.

 

[aholley777]

My understanding is that once you have it. You are free to swap it out, but I'd keep the original upper stuff to be able to swap it. Otherwise, I Believe you have to let the AFT know about the difference.

lol they'll know about the size difference in the feet up their asses.

 

[PORSCHE928S4]

My understanding is that once you have it. You are free to swap it out, but I'd keep the original upper stuff to be able to swap it. Otherwise, I Believe you have to let the AFT know about the difference.

I have been seriously thinking about it my 45 suppressor is rated for 300 bo subs and well AR pistols are a bit unwieldly the 300 bo suppressed in a SBR would be nice !

 

[solv3nt]

I've got a 9mm SBR with an 8" barrel that uses my Beretta 92 magazines.

 

[Willysmb]

Yes, you can also use a 9mm upper and your .45 Cal can. With subsonic ammo it would be quite satisfying

I regularly do this.

Not discouraging the use of 300BO at all, just another option.

Best regards.

WMB

 

[Trollinwaters]

The lower is serialized. I have run multiple calibers off my SBR lower. I kept the original upper that I used when filing paperwork just to be on the safe side.

 

[ilikegunspdx]

When you SBR a AR is the upper or lower serialized ? If it is the upper must you register a specific caliber or can you change the caliber of your SBR-AR ? If the lower is the registered part can you change uppers to your hearts desire ?

Lower is what's registered. Lower must be engraved with the new maker (assuming form 1). Calibers can change without any issue. You can put any upper you want on it. That's how I understand it and someone correct me if I'm wrong on any of that plz.

 

[ilikegunspdx]

I have been seriously thinking about it my 45 suppressor is rated for 300 bo subs and well AR pistols are a bit unwieldly the 300 bo suppressed in a SBR would be nice !

I have a sbr that sometimes is an 8.5" 300BLK. It has a sylvan arms folding stock adapter. Talk about tiny! Haven't shot it suppressed yet as my suppressor should be in soon. I did get a 5/8 x 24 tri lug adapter for it though so it is a quick swap with other 9mm subguns.

I'm too lazy to go swap it for a picture but this one from the internet is roughly the same size (stock must be deployed before shooting).



Re barrel length, 8.5" vs 10.5" or whatever energy levels can be seen on these graphs fyi. The first one shows % energy loss compared to 16" barrel (the annotations are for .223 not 300BLk). For 2nd graph Ignore the other calibers I just added those annotations to compare fpe for different calibers on 12.5" barrels.


Most of the time it lives as a .223 wylde which can be shot with stock folded. Same 10.5" brn-180 in .223 or 300blk from internet (drum too bulky for my taste)

4B7ACC7E-A36C-4AA8-B38F-47F33D9F885A.jpeg

• ilikegunspdx
• Feb 25, 2024

90F62D45-05A2-49CF-AD8B-6AFE4271ABD1.jpeg

• ilikegunspdx
• Aug 31, 2022

 

[CamoDeafie]

Triple stamp that thing and have fun!

SBR lower rec
MG FCG DIAS thingy (pre 1986 only, "transferable" and often as much as a new truck )

Suppressor

 

[Stomper]

lol they'll know about the size difference in the feet up their asses.

I hear-tell they often mistake their feet for gerbils….

 

[Lazyfaire]

Being an SBR usually depends upon the length of the upper, unless you have an auto sear. Personally I would want the 'etching' on the upper as that could go onto any lower you choose, but if you etch the lower then the upper could only go on that. Lowers are almost always serialized anyway. The upper is what makes it an SBR and fits the description on the stamp app.
The new etching machines are computerized and can be done in very small type (no ATF ruling on that...yet) and can be hidden anywhere. Again no rule on just where to put it.

 

[ilikegunspdx]

Triple stamp that thing and have fun!

SBR lower rec
MG FCG DIAS thingy (pre 1986 only, "transferable" and often as much as a new truck )

Suppressor

From what I've seen full auto is used less than people think. It's awesome if you can afford it but you can get a binary trigger for some fun time (I wouldn't recommend for self defense personally) or learn to bump fire more consistently. None of these options gets used much Imo possibly due to cost in ammo ($5-$6 per second, or $15-$18 per mag dump). Totally agree that receiver and suppressor is well worth the stamp cost.

 

[ilikegunspdx]

Being an SBR usually depends upon the length of the upper, unless you have an auto sear. Personally I would want the 'etching' on the upper as that could go onto any lower you choose, but if you etch the lower then the upper could only go on that. Lowers are almost always serialized anyway. The upper is what makes it an SBR and fits the description on the stamp app.
The new etching machines are computerized and can be done in very small type (no ATF ruling on that...yet) and can be hidden anywhere. Again no rule on just where to put it.

As I understand it SBR and a NFA registered full auto via auto sear are two completely different things and have nothing to do with each other except that both are required to be registered under the NFA.

Also as I understand it putting a less than 16" upper (whether etched or not) on any lower with a stock is making an SBR. If that lower is not registered as an SBR you have made an illegal NFA item.