Re: 338 rum & 300 GR BERGER
Some are faster and some are slower. Both on average shoot the 300 grain bullet a little over 2800 fps with top accuracy loads out of a 30" barrel. Either may shoot best in the 2700's. They shoot the exact same numbers and the same twist apply to both. They are the same thing and neither will out shoot the other. For the 225 run a 1-12 tist and a 1-10 will stabilize the 300 grainers. Some shoot a 1-9.5 if all they shoot are 300's but I have never had a problem with the 1-10 in either.
Predictions are difficult, especially when they involve the future