In June 2019, someone as the the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), Firearms Technology Industry Services Branch (FTISB), what was the correct way to measure a pistol equipped with a stabilizing brace that has a folding adapter (like my Galil Ace in the photo above).
They said that the overall length is measured with the brace in the folded position. So you can confirm this for yourself plus see their reasoning, click here to read the scanned PDF copy that has the names redacted for privacy’s sake.
Please note that I am not an attorney and this is not legal advice. I’m just passing along the ATF letter for people to read and interpret themselves.
I hope this helps you out.
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