I have found the 8 MM Mauser 98 to be a kicker too! Here are some ideas that have worked for me...I currently use a slipon type made by Pachmayr called the "SLIPON", this allows me to keep my Jugo M-48 Mauser in its original configuration, with the option of slipping on/off the black cushion glove on the stock end. I shot up some Turk 8 MM this Summer and it really helped to cushion the impact.
I had a brown copy of the same type of stock cover made in China that split after being taken on and off of my Russian Mosin Nagant rifle over the course of several years, so I would stick with quality on an item like that. Either way, the slipon is quite affordable, and can be used on numerous rifles, that is why I like it.
If you don't mind altering the stock/custom, etc. you could screw install a commercial type of butt pad, mail order, or a good gunshop would have it. I also had some success using a towel draped on my shoulder that helped to dampen the recoil on all of my bolt actions, but it would slip off and need frequent adjustment. So I went with the slip on type. :-)