Personally I tend to go with the vendor who brought the cartridge to market...

I have a 6-6.5x47L, and after necking down I had to trim back to 1.838" to get the cutter to hit the mouth on them all; 1.840" skipped better than 50%. Granted, the necking down process does tend to shorten things up a skosh, but not that much over that small of a change in caliber - 1.850" wouldn't have touched any of them