[TheVillageIdiot]

The correct way to measure the length of shell that will fit the gun is to measure from the face of the breach block to the front opening of the ejection port. The Auto 5 early versions were designed to tumble the shell out, not eject it like modern semi auto shotguns. Lots of discussion as to why it has this design and I won't repeat them here. Basically, if the breach bolt is more than 1/4 inch below the rear opening of the ejection port, you have a 2 3/4 inch shell gun.

What really matters is how your barrel is stamped. My 16 gauge Auto 5 clearly has the 2 9/16 inch ejection port, but the barrel is clearly stamped "special steel - 2 3/4 inch shells". You can have the breach of the barrel checked by a professional gun smith (note - professional) who can verify what length of shell can be safely fired from your gun. A lazy and dangerous way to test the length of shell is to take an empty 16 gauge hull and ream the opening so that the folds are completely open and the same diameter of the case sides. If the hull fits correctly into the barrel and you can close the bolt and the firing pin will work, then your gun can probably take a 2 3/4 inch shell.

Also remember that the friction ring can be adjusted for light or heavy loads. Some A-5's have the instructions for the orientation pasted inside the fore stock. Otherwise, the Browning web site has the manual with clear pictures. Adjust the ring orientation and see if it makes a difference.