'Funny' story: My go-to FFL guy calls and says he has factory SCAR 16 bbls in all lengths, and asks if I want to go SBR.
On a budget, and wanting the performance of a bbl no shorter than 14", I ask if the stock FN (PWS) muzzle brake pinned to a stock FN bbl comes to 16". He measures and assures me it does. Skeptical, I ask if he is measuring on an assembled rifle (to the bolt face), or on one of the barrels. After much back and forth, he repeatedly assures me of legality, and I tell him I'll trade my 16" bbl for a 14" bbl with a pinned and welded stock FN muzzle brake.
Ha-Ha on me, I pick it up, assemble the rifle to discover that I am a felon at 15 1/2"! I dis-assemble it like it's on fire, take the 'illegal' barrel to a friend's house for safekeeping, and call my FFL guy on the way to tell him what I think of his measuring skills and judgement. (he's really sorry.)
So now I am looking for a muzzle brake that performs "as well as" the PWS. (I don't care about the noise and blast, I love the way it works), but is at least 2 5/8" long (mebbe even with a washer) Most companies don't list an overall length online.
I know the vast wisdom of the forum will save me much time and trouble searching. THANKS!