I put a Boyds laminate stock on a PH 1200 given to me by my father in law and I used the large ring mauser stock. Boyd's website has a little tutorial as to how to tell the difference between a large ring and a small ring http://www.boydsgunstocks.com/Replacement-Stocks-for-Mauser-s/8.htm As has been mentioned, it is not a drop in by any means, but it's not all that tough if you take your time and check the fit as you go. When I say take your time, I mean this is not a job for a Sunday afternoon, you are likely going to have to invest 20-40 hours depending on how handy you are and the type of finish you use. A piece of advice based on mistakes I made - If you go with wood or laminate, don't put a finish on the stock until you're sure you've done everything you want to do with it. It sounds simple, but I didn't realize the hard rubber pad that came with the stock wasn't going to cut it until I took it out and put some rounds through the rifle. Ditto bedding the forend, as conventional wisdom is that rifles usually shoot better free floated.