This is to demonstrate that you do not need ( & actually do not want) a semi-auto for fast shooting with a shotgun.
With a pump, when working the slide, the ejection is automatic and slamming the slide back brings the barrel back on target. With an autoloader, you must physically pull the gun back onto target.
With the pump, it's an automatic result to the physical action of working the slide - properly. With the Rem. M870, my old J.C. Higgen's Riot gun and my current M835 Marlin, you must have your timing right as you cannot hold the trigger back for auto fire as the slide comes forward as in a Winchester M12 (or 1897). You must slap the trigger at the right time. Once learned, it does not take long to "get your timing back".