Phil, numbers match. Picture was taken in poor light and my shadow kind of go in the way a little. Forearm matches but stock nicely.

Still undecided if I'm keeping it. The loadings will be mighty limited since it has been suggested that I stay around 5,500 psi and no heavier than 7/8 oz. Basically I'm asking it to be a 28 ga. ( I would love one of the 28 ga. Reproductions someday). I will decide in the morning. There is another very nice gun on the market that I also like, even if it's not a Parker, and it would fill my needs nicely.

GH 16
 

I believe I bought that GH a few months ago. After my measurements I returned it.

With a heavy heart...I'm sending it back too. Just finished talking with Griffin and Howe. Time to build a shipping crate.

Using a wall thickness gauge such as a Manson (similar to your) Requires practice. The picture you posted shows the dial indicator at ZERO with the gauge laying down, so I can safely say, it was not correctly zeroed when you took your measurements.

No, it was actually zeroed in the position of use for measuring a horizontally secured barrel. I checked zero in it's natural horizontal position due to rod flex. I checked it with a metal strip of known and verified thickness, with the gauge in it's natural position for horizontal use and the readings are correct. The dial was only reset for the purpose of taking the photo. I took the readings 8 times and they came up the same each time.

Sounds like you understand how to use the gauge, but you'd be shocked to see how many don't.
John Hosford has a good video on YouTube on how to zero his gauge, and that method pretty much applies to all horizontal, hand held devices.

As I have explained and discussed many times before, horizontal with the barrels clamped horizontally is the correct and most accurate way to use a Manson gauge. Good work. I wonder what happened to that gun, considering that the bore measurements appear original? Maybe some Brit gunsmith did the barrel refinish and didn't get it right the first seven or eight times he restruck them.

Dennis, did you purchase the gun from Griffin and Howe? Would you recognize the gun if I posted better photos? If this is the second time they sold the same gun, they should be good enough to cover my shipping and insurance costs.

Yes Griffin and Howe is the engraving around the breech a little weird? I recognize the nice wood and weep holes. I made a offer with my return but they declined.

The solution is to ask a mega company like G&H to specify wall thickness before the deal goes through.