How do I fill out 4f of the ATF Form 1?

I'm intending to put together a 12.5" SBR: I have the lower and the ATF Form 1 mostly filled out (including CLEO signature). I'm trying to figure out how I can measure the overall length of the firearm without the upper. I know its 12.5" at least, and can measure the stock (fully extended or not?), but I cannot account for the length of the receiver. I've look everywhere online but it seems there are a number of different lengths possible, and I'd rather not guess and get this wrong.

Any help would be outstanding.

3 Answers

  • 9 years ago
    Favorite Answer

    ATF says to measure overall length with the stock EXTENDED, not collapsed. Just like guns with a folding stock have the overall length measured with the stock in the firing (extended) position.

    A quick way to figure out the overall length. Borrow an AR with a 16" upper and the same type of collapsable stock and same type of flash suppressor that you will use. Measure the overall length of that gun with the stock extended, and then subtract 3.5" from that number. That will give you the overall length of the same gun with a 12.5" barrel.

  • 9 years ago

    just look for the length of your particular brand and model of upper, then add it to your current calculations, if you don't know the brand, find it, it's not hard if you try. if you have your upper chosen, you just need to look it up, you really need to choose it before continuing. as for the stock, you need to fully close it and measure. your allowed to have all the parts in your possession as long as they're not assembled, so I'd wait until you have your upper before finally sending the papers out.

  • Anonymous
    9 years ago

    If you post this on you will get better answers

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