I have been convinced I was wrong about the curved tubes. Joe had a conversation with Kirk Merrington. Joe relayed as best he was able what Kirk said in a thirty minute conversation to me.
This is my understanding of what Joe's understanding of what Kirk said. The third wife bit all over but I felt I needed to explain what changed my mind.
The gunmakers intended for the tubes were to be straight in the barrels as per Miller, Stan, Shotgunlover and others. If jigged up properly and with straight tubes they both tubes would shoot to a point. Each tube needed a convergence of about six thousandths per inch of bore which is .012" for both tubes which is the number Miller has been giving out for his Smiths I believe. The .072" difference at the muzzle in a two frame Parker 26" and two frame Parker 32" gun was made up by the flat that was filed on the flat filed on each tube at the muzzle.
Parker barrels made before 1900 were made with straight tubes as described above. After 1900 something changed in their method. After they were brazed together at the breech but before they were soldered at the muzzle they drove wedge in between the barrels. The wedge was driven in just downstream of the hook. They drove the wedge in until the flat surface filed on the outside of the barrel at each muzzle touched at the right angle. This new process created a bow in Parker barrels made after about 1900.
I am unclear if Kirk said regulating the tubes to have the same POI by filing the chokes was normal for the top tier guns. He said the Birmingham makers did not do that.
I hope Joe will post a more detailed account.
I repeat: I was wrong, Miller, Stan, ShotgunLover, Craig, and others were right. The competent makers did not intentionally install curved tubes in their SxS. Thanks for the interesting discussion.
