Re: .338-.378 KT info?
If you are looking for a big 338 the wildcats off the 378 wby case with the shoulder pushed forward and changed to the standard shoulder do very well. Also look at one of the 338-416 Rigby wildcats. If you are doing a custom big 338 these are the tops and will exceed the lapua and 338-300 ultramag that some on here call edge and several other names by up to 300 fps. I have seen them exceed 3200 fps with a 300 grain bullet and 30"+ barrels.
Predictions are difficult, especially when they involve the future