I'm pretty sure the 'CharlesC' who posted the original pictures here, which no longer display, is the same person as 'Charles' who posted a few pictures in his online album here:
http://www.hunt101.com/showphoto.php?ph ... puser=6613
That image shows the internal changes he's made to the grip of his IZH-46m, allowing a front and a rear Allen bolt to be adjusted and thereby adjusting the grip's rake. It's a neat enough solution. Hunting around in his pictures there are a couple of others related, scattered a bit randomly in the collection.
I might have saved myself considerable labour by using this method, but since I really wanted to do away with the front bolt I designed a slightly different way of doing the same thing. Posted a thread here about that:
http://www.airgunforum.ca/forums/topic39891.html
There are two grips in that thread, one the original used for prototyping and the second the one I'm still using, made of maple. I don't find any need to adjust the rake actually, haven't fiddled with it in the past couple of months as it seems perfectly fine to use the same rake for both 7metre and 10metre ranges. At least not enough difference for me that the difference impacts my average. So again, were I to save time in doing this I'd likely not bother making it adjustable. Easier to just figuring out the correct angle, then make a grip fitted at that angle. So the adjustability seems more of a testing thing, a tool for finding the right fit per an individual's needs. And of course such adjustments make mass-marketing of a grip a lot easier in terms of accommodating a variety of shooters.