This would be the RWS item number 2119242 which is a 293gr. UNI (TUG?) @ 2427fps from a 23.6" barrel.
I'm betting the RWS numbers are pretty darn close to actual performance.
A look at "Real Guns.com" load data shows 19 out of 36 loads that meet or exceed the 3900fp energy requirements, with bullets ranging from 270gr to 325gr, using a Ruger M77 with 23" barrel. The most common powders used were H414, Re-17, and IMR 4895.
A check of 45-70 loads showed 3500/3600fp of energy as the maximum attainable.
I'm sure most have heard of Kevin Robertson's 9.3x62 that he said had taken over 650 buffalo in its time, and how he actually preferred it for his clients because they usually shot it better than a bigger rifle.