Parker D grade 10 gauge questions

[Researcher]

If that cylinder choke is being measured with a plug gauge, that is not an issue.
The bores of an 1889 vintage Parker Bros. 10-gauge are very likely to be much closer to .800" than .775". What are actual measurements with a bore micrometer?

[Dennis Martin]

The choke was measured with a flat Galazan gauge. This is probably the only measurement that I'll be able to get. So if I understand correctly, the choke is relative to the actual bore. If the bore is "oversize", the muzzle could measure larger than a more conventional muzzle and still have the constricting properties?

[6pt-Sika]

Originally Posted by Dave Noreen

If that cylinder choke is being measured with a plug gauge, that is not an issue.
The bores of an 1889 vintage Parker Bros. 10-gauge are very likely to be much closer to .800" than .775". What are actual measurements with a bore micrometer?

Well now my 1889 EH measures M/IM with a flat gauge . So going by what you say it should be tighter going by the nominal bore diameter ? Is that true also for my Grade 2 circa 1884 top lever 10 gauge , that one by the flat gauge is IC/M both guns have barrels that are uncut .