New member, new to me Parker GHE 2 7/16 chamber

[Pa SxS]

I don't ever remember seeing chamber lengths in 1/16" increments until Scott contacted me about a letter I did for him a few months ago. I looked at the stock book again and it sure looks like 2 7/16". Now the 7 could have possibly been a 9 but with the loop in the 9 not closed. Those old records are many times faded or the person who entered it just wasn't careful. The gun 1 S/N above Scott's gun had the same chamber length and was written exactly as Scott's gun, looked like 2 7/16". I decided to look at other pages in that stock book and found what looks like another 2 7/16" chamber. I looked farther and found an entry in which there is no doubt. Attached is the entry for Scott's gun and the other is the one which is clearly 2 7/16". I did find an entry listed as 2 1/2" in that book.

So why would Parker chamber for 2 7/16"? Why would Parker make it 1/16" shorter than 2 1/2" which according to The Parker Story as of May 1920 all guns 12ga. thru 32ga. had 2 1/2" chambers standard? Scott's gun was made in 1926. At some point in time later, Parker seemed to use 2 5/8" chambers as standard unless otherwise asked for.