Thanks Der Ami. Some of that I did know, some I didn't.
There was not any information on what loads were used to regulate the gun I have and it is the only double rifle that I've ever seen with my own eyes so, you're right, I don't have a whole lot of experience. I did, however, consider what would happen if I put a 180 in the lower barrel so, just for fun I put a 150 in the over barrel and a 180 in the under barrel (the opposite of the four shot group above) and actually put the two additional shots on the same piece of paper I just cropped them out in the above photo...see below for the target with all six shots included.
The upper barrel with the 150 grain bullet shot 4 inches above the centerline and the under barrel with the heavier bullet shot about 4 inches below the group. I've shot enough of each round, at this point, that there is definitely a predictable pattern emerging and that pattern is saying that with the same load in both barrels the over barrel is going to shot about 3.5" to 4" higher than the under barrel whether the load is the 150 grain or the 180 grain...
I have actually recorded every shot as to cartridge, distance to the target, and horizontal and vertical distance from the point of aim and captured every scope adjustment long the way. I have all of these in an Excel spreadsheet. I can plot any combination of shots in an X-Y graph and include scope adjustments or not. I have put a lot of thought into this.
I am still open to thoughts and suggestions but I am coming to terms with having to put a different cartridge in each barrel. Actually, I'm kind of excited about having the choice of bullet weights that both hit about the same point of impact.
