There is no iron sight for shotguns that is faster than ours. Our 20 Gauge Universal Split-Ring Shotgun sight is designed to go behind factory front sights and over magazine/barrel clamps. Removal of factory sights and clamps are no longer necessary. With our 20 gauge shotgun sight, start with 020" of shim for an approximate 25 yard zero with slugs. Approximately, each increment of .002" to .0025" of elevation shim will affect bullet impact by 1" at 25 yards. With the tools provided with each sight kit, most will be able to install our shotgun sights without professional help.