New here guys, but I heard now correct me if I'm wrong, but over at Beartooth Bullets Marshall stated for the .35 Remingtons the .359 dia cast bullets shoot the best in these 336 micro groove barrels.
JB,
The throat of the chamber should be measured to really know how to size your bullet. The bullet should not be over .001" smaller than throat diameter. The bore should also be slugged, to see if any tight spots are present, in order to remove them. That's the correct way but, I have in the past, slugged the bore and sized my bullets .002" over and got good results.
Micro-Groove barrels have, in the past, been oversized which contributed to the misconception that they wouldn't handle lead alloy bullets. Whenever a bullet is undersized .001" to .002", accuracy is nill at best and non-existant at worst. I have a .30-30 micro-groove that only measures .307" and handles .309" sized bullets fine, producing groups at 100 yards in the 2" range. HTH