Of the two cals the launch platform is often a driver. I am a classic mauser 98 and double rifle fan. My .40's are a .404 and 416/500 (wouldn't mind a 98 in the Rigby but I already have one .40 more than I need). A number of friends are Blaser R series fans which means their .40 is the .416 Rem. I am pretty sure no cape buffalo in Africa could discern any difference in the three.