I did strip, sand and then dye the wood before applying the BLO. I did not check the fit of the butt plate during this process. Definitely going to during my next restoration though.
Wish this was the case. If I lined the notches up, it would show an equal gap on both the top and bottom of the butt plate. I just have it pushed all the way down in the photo.
Before you start the next restoration, may I offer some suggestions on fixing this one.
IF the wood was that wet that it shrunk that much, you have to wait until the wood stabilizes. One way is to make careful measurements with a caliper/micrometer. The measurements are made and logged until the measurements don't change anymore. During that time you can decide what you want to do, if anything.
You have a bad situation in that the plate has a horizontal toe extension, and it doesn't fit anymore. In my opinion and experience there are three options. One is eliminate the extension, and the other is adding wood or (3) brass to the bottom of the toe to make up the difference.
Eliminate the extension: I don't have the parts in front of me to look at, but can the extension that passes forward under the toe be eliminated and the remaining plate shaped to the new shape of the butt stock? If so, this fix would likely be the easiest and cause the least frustration.
Adding wood: I have made many repairs to stocks by cutting or carving wood out, and carefully fitting in pieces of the same stock material to build up the area, then shaping to fit, and refinish. If you brought the stock to me, I may cut the bottom of the stock off, parallel with the top, and glue the appropriate wood on, and shape so the butt plate drops down and fits again. Then the sides can be trimmed and polished to the stock. The issue with this fix is that it's treated with BLO, and depending on how much it has soaked into the wood, the glue may not hold.
Adding brass: I don't know how handy you are, but if you are going to be refinishing stocks with brass furniture, you might have to learn to work with it. Measure the difference between the stock and the horizontal plate extension, and get a piece of brass the thickness of that measurement, and make a decorative "clasp" to take up the length and thickness. It would be shaped like a "U", taller in the back, by the plate, and tapered towards the front. Shape it to fit the stock, and the butt plate extension would "piggy back" on top of it. If the bottom of the toe is flat, maybe just adding a flat piece of brass to it, to take up the difference.
Jim