Thanks for the replies, guys.
I'm aware that many think that building a big bore on a smallring 98 is pushing the limit, but I also know that it's been delivered that way from factory (not Brno, but original M98 smallring sporters.)
about the stock, i'm afraid its in a rather poor condition. It's been broken and repaired, and somone put a file or sander to it and removed all the checkering.
I have not yet desided on what to do, but i do have a 10,75x68 barrel on hand for a good price, and, that's what got me thinking.