[Austin W Hogan]

Take a look at the Super Fox article in the most recent edition of DGJ. I made up a pretty sensitive measuring device to measure the bores chokes and chambers of that gun and measured several of my own guns before taking it to Julia's. That instrument had an uncertainty of about 1/16 inch in measuring chamber length.
A blade or plug type chamber gauge is a fail safe design, in that it will stop at the point where chamber diameter equals the the width or diameter of the gauge, even if it does not contact the forcing cone. The taper of the chamber is about .005 inch per inch. I measured several guns that showed <2 1/2 or < 2 5/8 chambers with a blade gauge, that were only a few thousandths smaller at the point that the gauge stuck, compared to the beginning of the forcing cone.
I recieved an e mail from Bob Foege indicating his bore gauge will measure the chamber profile much more easily than my set up.

Two points to remember with regard to Parker chamber depth:

The catalogs offer any chamber dimension of the customer's choosing at no extra charge. A customer that wished to shoot 2 inch English shells could have had his gun chambered accordingly.

For the good of the gun, there should be a little clearance between case mouth and forcing cone. Parker metal may handle the extra kick and pressure caused by case interference, but the wood will eventually suffer, spreading at the wrist or chipping behind the tang.

The present day SAAMI spec for 2 3/4 inch shells is 2.750 -.100 . I have measured several batches of modern AA and Rem target loads and find fired shell length to be 2 3/4 inch minus 1/16 to 3/32 inch.

Best, Austin