I need some advice in developing a load for my bolt action Mauser 98 rifle in 338 Win Mag. The application is Oryx hunting which are described as tough animals with fairly long shots (250-300 yards). I checked my bullet supply and found 338 Hornady 225 SST's and 225 Nosler Partions. I figured the 225 NP's would be ideal and thought I would load up a few of the Hornadys of the same weight to get an approximate load and then fine tune with the more expensive NP's. I loaded up the IMR 4831 recommended loads from the Hornady manual from 58.2 grns to 69.9 grains in 100 fps increments (roughly 2 grns). I also loaded up three NP's each at the penultimate and max (69.9) in the Hornady manual. All loads were crimped with the Lee Factory crimp die and used Win Large Rifle Mag primers. I seated all the bullets to the same depth as the cannelure on the SST's. Results were poor. Groups were 4" at 100 yards, down to 3" at max. The rifle will do much better with factory Remington 225 Core Lockts. Other CGN posts suggest higher/hotter loads with 225 grn bullets and IMR 4831 (up to 73 grn). My groups did get smaller at max but I am somewhat reluctant to go above published max's ( I am a new reloader). I am hoping someone can suggest a 338/225 NP load for my next trip to the range. I also have IMR 4064 and H380 and will buy a new powder, if that is what it takes but IMR 4831 seems to often recommended for the 338 WM. Thanks for any advice.