I looked but did not see anything posted recently for pistol braces...So-
Googled and found:
https://www.badassoptic.com/are-pistol-braces-illegal-now/
Bottom line up front, pistol braces are legal again based on a Fifth Circuit Court ruling.
Took this picture several years ago of the result of a squib load. As seen, the bullet failed to completely leave the barrel.
A squib is when the ammunition, when fired, may not generate enough energy for the round to leave the barrel.
Indications are a "Pop" instead of a bang or...