1:10" should be fine for all bullet weights up to 250grs.That's standard on most .30 cal rifles,I think your barrel length is a little short for that cartridge;28" would be better.
I can't think of any factory loads that have 200 gr bullets,there isn't that many in any weight as yet,we'll have to see if Remington are going to offer more bullet weights in the near future,it depends on how many they sell.
MagnumManiac
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