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Chaz,
I know CAD can be a wonderful thing, when I retired we were sorting out interferences of utility lines in buildings we were building, but it depends on good input. You can't count on the existing bases being parallel with the rifle barrel. They were soldered to the shotgun barrel, after being "scraped in" for a close fit joint. At this point, they would not necessarily have been parallel to anything, or level. The top of the rear base, and the bottom of the dovetail in the front base would have been "skim cut" milled, to bring them parallel and level. The surfaces they would have been made parallel to, are the "flats", under the barrels next to the lugs( the barrel bundle was set in the milling vise with the flats on top of the vise jaws). Note that so far the rifle barrel hasn't been used to align anything. It would not likely be parallel to the shotgun barrel, rather, it would likely have some amount of convergence built in. The part of the procedure that aligned the scope with the rifle barrel was the bore sighting to determine the height of the rear mount, as described above. To adjust the height of the mount to that determined by the bore sighting, the bottom of a "too tall" mount would have been milled to the required height by milling to a line scribed on it by the caliper used to measure the height of the adjustable block ( " jack"). This was likely a direct transfer, and the actual measure wouldn't necessarily even be known. This milling would have extended the length of the "feet", which would have been shortened to a length determined by measuring the depth of the slots they fit into( with the caliper) which was also transferred directly to them. They were filed to fit the contour of the barrel, so they would fit all the way in( spotting and fitting by scraping/filing to fit the base closely, but with a little clearance at the very bottom, so fitting the "slider", can pull it down to remove the "slack"). Once they were fit up, they were held tightly in the base and marked with a scribe( through the slot on the side of the base, at the bottom of the slot), to locate the notch into which the "slider" would fit. This notch was cut with a "form cutter", similar to a slitting saw ground to an angle on one side. I would have been cut so the scribe line was left and the notch was that far above the bottom of the slot. Now, your task is going to be doing the same thing, but with a foot that has already been milled to fit entirely different bases. If you are lucky and your foot is too high, you will have to shorten it by milling the bottom and welding up the notches to be refit. If it is too short, the easiest thing to do would be solder/glue a shim to the bottom and extend the feet by welding. Of course, this all assumes you don't want to buy new parts from New England Custom Guns.
Mike
I know CAD can be a wonderful thing, when I retired we were sorting out interferences of utility lines in buildings we were building, but it depends on good input. You can't count on the existing bases being parallel with the rifle barrel. They were soldered to the shotgun barrel, after being "scraped in" for a close fit joint. At this point, they would not necessarily have been parallel to anything, or level. The top of the rear base, and the bottom of the dovetail in the front base would have been "skim cut" milled, to bring them parallel and level. The surfaces they would have been made parallel to, are the "flats", under the barrels next to the lugs( the barrel bundle was set in the milling vise with the flats on top of the vise jaws). Note that so far the rifle barrel hasn't been used to align anything. It would not likely be parallel to the shotgun barrel, rather, it would likely have some amount of convergence built in. The part of the procedure that aligned the scope with the rifle barrel was the bore sighting to determine the height of the rear mount, as described above. To adjust the height of the mount to that determined by the bore sighting, the bottom of a "too tall" mount would have been milled to the required height by milling to a line scribed on it by the caliper used to measure the height of the adjustable block ( " jack"). This was likely a direct transfer, and the actual measure wouldn't necessarily even be known. This milling would have extended the length of the "feet", which would have been shortened to a length determined by measuring the depth of the slots they fit into( with the caliper) which was also transferred directly to them. They were filed to fit the contour of the barrel, so they would fit all the way in( spotting and fitting by scraping/filing to fit the base closely, but with a little clearance at the very bottom, so fitting the "slider", can pull it down to remove the "slack"). Once they were fit up, they were held tightly in the base and marked with a scribe( through the slot on the side of the base, at the bottom of the slot), to locate the notch into which the "slider" would fit. This notch was cut with a "form cutter", similar to a slitting saw ground to an angle on one side. I would have been cut so the scribe line was left and the notch was that far above the bottom of the slot. Now, your task is going to be doing the same thing, but with a foot that has already been milled to fit entirely different bases. If you are lucky and your foot is too high, you will have to shorten it by milling the bottom and welding up the notches to be refit. If it is too short, the easiest thing to do would be solder/glue a shim to the bottom and extend the feet by welding. Of course, this all assumes you don't want to buy new parts from New England Custom Guns.
Mike
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