The explanation I heard was the R100 is the Olympic/Biathlon version.
If possible you should check the velocity of it. The R50 is around 1070 but will vary lot to lot as does Eley.
Eley publishes the velocity on their Match grades and so does Lapua via a special formula.
by placing a 3 in front of the first two numbers of the lot number you have the velocity in metres per second. Multiply by 3.28 and you have the velocity in fps.
RWS produces match ammo for Federal and the velocities are 1080 for SV and 1200 for HV.
I have tried both (R50 and Federal) and the SV is very good but the HV leaves a lot to be desired. The two bricks of Federal HV will probably kill gophers as there are days when it is on par with MiniMags.
Regardless, the price is good and at 1200 fps it will be good for varmints.