Yes, with right bullets the 8 mm RM and its European cousin 8x68S are extremely effective.
They both have flat trajectory, are very precise and their terminal ballistics are phenomenal. In Europe, you find a bunch of good bullets for them too, like Blaser CDP, Brenneke TOG, Lutz Moeller MJG and many more. Looking at this site some bullets for the special purpose of LRH may be missing. People here are demanding Berger VLD or ABLR.