I've used the Hornady factory ammo (570gn soft points) and it regulated well but shot low - I had to use the 75yd sight for 50yds.

My reloads of 570gn Woodleighs (both soft pont and solids) regulate well - I use Graeme's suggested loadings.

I also have loaded 440gn Woodleighs with the same powder load as the 570gns (as a "reduced load" but I can't feel a difference to be honest) and, once again, good regulation, and same POI as the 570gns out to 50yards. I can use the correct sight settings with my reloads (well have only tried 50yds).

I have also used 570gn soft point Bertrams, same load as above, same results. I'm going to try some banded monolithics (probably the Woodleigh "hydraulically stabilised") one day to see.

My double is a Merkel BTW.