Anyone use these barrels before? Looking for a barrel with removable chokes for my auto 5 magnum. Found these on tradex, Verney-Carron Hastings Wadlock Barrel (straight rifling) For Browning Auto 5 in 12GA x 3 Inch Magnum. 28 inch with Ventilated rib. They worth $400? I have never heard of straight rifling before.