A Sixth Circuit brief says 1.17 million registered SBRs are protected arms and that the federal registry rests on a 1934 drafting accident—not American historical tradition. IMG Jim Grant One-tenth of an inch can separate an ordinary rifle from a federal felony. Now four major gun-rights organizations are asking the Sixth Circuit to explain how that arbitrary line can coexist with the Second Amendment. The National Rifle Association, Firearms Po…