I tried between 0.010" and .140" with my 7 mm Ultra/Sendero using 168 gr. VLD's. Nothing gave me better than 1.5"-2.5" groups at 100 yds. I went through a box of Bergers and nothing seemed to work for me. I have given up Bergers for this rig.
I tried Barnes 160 gr. MRX with US 869 at 3300 fps and most groups, during load development, were less than .7". Accuracy inproved with charge weight. I seated to the to the OAL recommended in Barnes manual #4 (I would have to check my records for acctual OAL); I loaded two grains under Barnes reccommended max load, and expected to achieve about 3150-3180 fps. The MRX is pretty expensive and US 869 is proported to have poor temperature stability, so I will try a 162 gr. Hornaday SST next with an appropriate Hodgdon extreme powder. It has been a bit chilly lately when I have had time to go to the range lately, so the SST's will have to wait.