Ovatafford, I have never had a problem getting to the lands with a factory mag box and 210 Bergers. This includes two 300 wins that were chambered with standard match reamers and also a few 700 Senderos I have worked up the load for. I better add , please start low with the powder charge of H-1000. One of the senderos started showing pressure signs at about 75.5 gr. It shoots very well and is now happy at 74.6 gr and we shoot it to 1400 yards.
But others are just as happy at 77 gr. So there is no way to know what your rifle will like other than starting low and working up.
If you have some Lapua Headstamp brass you have the best brass you can get for this rifle. IMHO, and if you feel any reason to use something else I will be glad to buy your Lapua brass from you...