There's something very curious about 21 that has always bugged me. There is a large hole, going by memory maybe 1/2" or 5/8" in diameter, that runs up through the middle of the butt (under the buttplate) about as far (again going by memory) as the front of the box. It's very weird. What is even weirder is that the box mortise cleanly cuts into this hole, so the bottom of the box mortise has like "half a hole" or maybe think more like a rain gutter running across the bottom of the mortise on a diagonal. then at some point someone partially plugged it with a dowel to basically isolate the mortise from the area under the buttplate. That plug seems later but then it also appears that the inside of the box mortise has a much fresher refinished look, so if the mortise is original from day one or just very old (i.e. in working life) any real age has been largely obliterated by glue and more recent staining.
I'm just going to say it and I'm sure someone or maybe multiples will get huffy wth me for saying it but the only way this makes sense to me is if I figure that the hole was originally there when the rifle was stocked - probably something to do with holding the stock in place kind of like a lathe center - and later on, someone added the box and had an "oh $#@*" moment when he cut the mortise too deeply and cut into the hole. Of course the original builder could have done this also, but given the quality and high competence of the stocker (whoever he was) it's hard to believe that he would have made such a gross error. I suppose possibly if it was a busy shop with many apprentices, an apprentice might have done it. Generally the box mortise is cut after the buttplate is installed, so maybe one person roughed out the stock and installed the buttplate and then a different person cut the mortise and accidentally chopped into that hole. I really don't know but this has bugged me ever since seeing the gun, and that's been a long time now.
Some of these were definitely stocked by the same guy, 21 and 22 in particular. 20 is also a strong possibility although there are some differences so possibly it was either somewhat earlier, or maybe a different hand, very difficult to tell. I would love to know if 22 or 20 have this same hole up through the stock but obviously people nowadays are very hesitant to remove furniture; for one, it breaks patina build up and also it sometimes reveals things folks really don't want to know!
Don't beat me up too much, anyone who has handled this gun surely has wondered about this. I'd love to hear alternate explanations.