SBR Lowers and Caliber Changes

[DMW1116]

I thought I’d look into making a 300 BO upper for one of my current lowers and have that lower designated an SBR. However I hear once it’s engraved as a lower for 300 BO I won’t legally be able to run a 5.56 upper on it even if it is 16” or more in barrel length. How does that work as far as going from Caliber X with an 8” barrel to Caliber Y with a 16” barrel on an SBR lower?

 

[mavracer]

You only need to notify the ATF of a caliber change if you can't return it to the original.

 

[dogtown tom]

.... However I hear once it’s engraved as a lower for 300 BO I won’t legally be able to run a 5.56 upper on it even if it is 16” or more in barrel length....

Whoever told you that is wholly ignorant of federal law/ATF regulations. Probably the same guy who believes a Safe/Semi/Auto marking means its a machine gun.

Stop asking that guy questions.

§ 479.102 Identification of firearms.

(a) Identification required. Except as otherwise provided in this section, you, as a manufacturer, importer, or maker of a firearm, must legibly identify the firearm as follows:

(1) Serial number, name, place of business. By engraving, casting, stamping (impressing), or otherwise conspicuously placing or causing to be engraved, cast, stamped (impressed) or otherwise placed on the frame or receiver thereof, an individual serial number, in a manner not susceptible of being readily obliterated, altered, or removed. The serial number must not duplicate any serial number placed by you on any other firearm. The frame or receiver must also be marked with either: Your name (or recognized abbreviation), and city and State (or recognized abbreviation) where you as a manufacturer or importer maintain your place of business, or in the case of a maker, where you made the firearm; or if a manufacturer or importer, your name (or recognized abbreviation) and the serial number that begins with your abbreviated Federal firearms license number, which is the first three and last five digits, as a prefix to a unique identification number, followed by a hyphen, e.g., “12345678-[unique identification number]”; and

(2) Model, caliber or gauge, foreign manufacturer, country of manufacture. By engraving, casting, stamping (impressing), or otherwise conspicuously placing or causing to be engraved, cast, stamped (impressed) or placed on the frame or receiver, or barrel or pistol slide (if applicable) thereof certain additional information. This information must be placed in a manner not susceptible of being readily obliterated, altered, or removed. The additional information shall include:

(i) The model, if such designation has been made;

(ii) The caliber or gauge;

(iii) When applicable, the name of the foreign manufacturer or maker; and

(iv) In the case of an imported firearm, the name of the country in which it was manufactured. For additional requirements relating to imported firearms, see Customs regulations at 19 CFR part 134.

 

[Jonny2guns]

Why would you engrave it?

 

[dogtown tom]

Why would you engrave it?

Because federal law requires certain information be engraved on an NFA firearm. When you file the Form 1 for "making", you agree to mark it as required.

 

[berettaprofessor]

Because federal law requires certain information be engraved on an NFA firearm. When you file the Form 1 for "making", you agree to mark it as required.

Not with the recent "no-stamp" SBR's...no engraving required. Now if that program just stays "approved."

 

[Lo-Profile]

I thought I’d look into making a 300 BO upper for one of my current lowers and have that lower designated an SBR. However I hear once it’s engraved as a lower for 300 BO I won’t legally be able to run a 5.56 upper on it even if it is 16” or more in barrel length. How does that work as far as going from Caliber X with an 8” barrel to Caliber Y with a 16” barrel on an SBR lower?

The lower is the NFA item, not the upper. Shouldn't matter what upper you have on it.

 

[jmorris]

However I hear once it’s engraved as a lower for 300 BO I won’t legally be able to run a 5.56 upper on it even if it is 16” or more in barrel length.

You need to talk to different people.

I generally just call the folks on Needy Rd for my questions. Keep the number to the NFA branch in my phone (304) 616-4550.

 

[dogtown tom]

Not with the recent "no-stamp" SBR's...no engraving required. Now if that program just stays "approved."

Thats because that requirement was specifically exempted by the AG and only for Form 1's filed under the arm brace forbearance.

 

[dogtown tom]

The lower is the NFA item, not the upper. Shouldn't matter what upper you have on it.

No, the entire firearm is an NFA firearm when configured as such. You could have a factory SBR Colt AR15 w/11.5" bbl. (I do)
If I attach a 16" bbl it is no longer configured as an SBR and not an NFA firearm.

 

[AlexanderA]

Probably the same guy who believes a Safe/Semi/Auto marking means its a machine gun.

Currently (noting that the ATF positions have changed over the years), the only thing differentiating a machine gun lower from a semi AR lower is the presence of the "third hole." ** It doesn't matter if the FCG pocket is milled out to M16 specs.

** Marking the "third hole," according to the ATF, is the same as drilling it. (This arose because some people were milling an annular groove at the "third hole" location, to simulate the auto sear pin.) Otherwise, "Safe/Semi/Auto" markings don't matter.