It’s not, length restrictions apply to rifles not firearms make it as a pistol and as long as you don’t put a stock or a vertical forgrip on it it will be perfe

It’s not, length restrictions apply to rifles not firearms make it as a pistol and as long as you don’t put a stock or a vertical forgrip on it it will be perfectly legal. You can also have an open bolt semi there are quite a few conversions that didn’t went closed bolt.