Some years ago while attending the NSSA World Skeet Shoot in Savannah, GA, I had an interesting conversation with a Winchester Factory rep. We were discussing the Model 50 automatic, and the fact that it was never chambered for the 3" shell. He related to me that he had at one time worked for Simmons, and that they did convert the M50 for 3" shells. They did so by cutting a chamber with a sharp shoulder at 2 3/4" and no forcing cone. When fired, the first 1/4" of the shell would cut off cleanly and thus allow ejection. These were paper shells, and they had to stop this modification with the advent of plastic hulls, since they wouldn't cut off cleanly. I wonder what kind of pressures were created in those chambers?