Aim Surplus has some 14” Remington 870 Barrels for sale. These are police trade in. If you want to build an SBS 870, you know how hard it is to find these barrels.
https://aimsurplus.com/products/leo...0-12ga-3in-magnum-145in-barrel-w-rifle-sights
https://aimsurplus.com/products/leo...0-12ga-3in-magnum-145in-barrel-w-rifle-sights