Another "thanks" to Stephen for the information supplied.

Thanks for the kind reference to Bob Hynden as two of my rifles were made by Bob. He and I had planned a 45-90 DR on an action that he had but he passed away before we could begin the project. When Marie was selling some gun making things from the estate, she learned that another client that was first in line for the Beretta .45-70 DR would not be buying it, she asked me if I would be interested.

My response was "Heck yes" (I was unaware the rifle existed before then) , as extending the chambers would make the 45-90 that I wanted!
Bottom line is that after I shot the 45-70 DR a few times and proved the barrels to be individually sub minute of angle accurate, it went to Aaron Little in East Texas where the chambers were extended, the barrels regulated, and the fixed scope mounts replaced with quick release mounts. I am happy to report that the rifle regulation is tight at 45 yards and still good at 100 yards! To field test it, I shot a Blackbuck at 100 yards recently and it went over like a steel target.

BtW, I had loaded a set of trial ammo with North Fork 350 SS from 60 -67 grains of N133 and found that very accurate but chose to forego shooting the hotter loads until my son and I get out with my 1886 45-90 (both rifles have 26 inch barrels) and barrel mounted Chrony, weather and other issues have delayed our plans so far. The velocity results will be reported!