Johnny Guest,
Great idea working up a load that duplicates the MkVII round, so as to be able to use your sight calibrations. The 174gr South African I have been using is most certainly slow. I've got my micrometer dialed up to ~400yds to be on at 200yds. Five clicks up from that to 300yds. And the battle sight is about a foot low at 300yds and maybe 6" high at 200yds. I figure it would be zeroed at ~230yds.