A shotgun stock's fit to the shooter is important. It will also affect perceived recoil. Does yours have one of those "comfortech" stocks on it? I don't believe I've seen a picture of your fairly newly acquired Benelli.
2 3/4" is more than adequate for 12GA. The chambers for my Ithaca 37 and Remington 870 are only 2 3/4". They've both been flawless in function and are older than I. I would be surprised if your Benelli has any problems other than that isolated malfunction. You should really try it on some aerial targets.