Just was given an older 16 ga Browning auto 5
The barrel says 16.8. Choke 16.7
Wondering if one of those numbers was chamber length.
Its an older gun with the safety in front of the trigger

Those numbers are in millimeters and they represent the interior diameter of the unchoked portion of the barrel and the I.D. in the choked portion. The bore diameter of 16.9 mm is approximately 0.6653543 inches. The choked diameter of 16.8 mm equals approximately 0.6614173, which means that barrel (if unaltered) has a choke constriction of ~0.00394 inches or rounding off, 0.004 inches. Based on my limited knowledge, that would indicate a Skeet choke.

Here are some links off the old 16ga forum that you might find interesting:
http://www.16ga.com/forum/viewtopic.php?t=18620
http://www.16ga.com/forum/viewtopic.php?t=1531


The length for a 2.75 inch chamber will be 70mm, and you might see a stamping of 16-70 which would indicate a 16ga gun with a 70mm length chamber.
Have fun with the old Auto 5 - they were classy shotguns.

Thanks, I was hoping that was somehow a code to give me a chamber length. Seems my newer 16's are marked 70mm but the older ones are unmarked. I have some Ely and RST 21/2 " Shells, and load short shells for my older guns, so I won't alter it. Someone put a Polychoke on it so its just a shooter, and kind of rough anyway. Perfect rabbit and squirrel gun after deer season.

Being a pre-war gun, it will have the 2 9/16" chamber unless it's been altered. Many of the short chambered guns function fine with Remington ammunition as the hulls are actually a bit shorter than standard. At least that was the case before Remington was acquired by Federal.

All I have remaining is a 1938 model that had been altered to accept the longer shells. The alteration makes the gun look like the barrel is not inserted into the receiver and tightened correctly. For that reason I was able to pick mine up for a song at Cabela's. They thought something was wrong with it and sold it as a wall hanger!