AFTE Store - Capability of a Winchester Model 1300 Shotgun to Extract and Eject a Fired Shotshell without Actuating the Forearm

The circumstances found at a crime scene prompted an investigation into the functionality of a Winchester Model 1300 pump action shotgun. A fired shotshell was found on the floor after an alleged suicide. The question: Is it possible for a fired shotshell to be extracted and ejected from the chamber of this shotgun without manual actuation of the forearm? Testing of this shotgun showed it to be capable of unlocking the chamber and moving the bolt rearward without manually sliding the forearm.