tom, what is your rifle?
The .275 Rigby was the first high-velocity loading of the 7x57mm Mauser. Some ammunition is loaded to a lower pressure, for the older 1893, 1894, and 1896 Mausers - for example, with a 139-gr bullet at 2,660 FPS. Federal, Remington and Winchester would be like this. So would S&B with their 175-gr load at 2,340 FPS.
Some loads are more like the .275 Rigby, with 140-gr bullet at 2,800+ FPS. Norma, RWS, Hornady Superperformance, and others would fall into this category. These are for modern actions, like the 98 Mauser, Winchester Model 70, Remington 700, Sauer, Steyr, Heym, Sako, BSA, Parker Hale, etc.