425 A-Square Express load data

[cwhuntsalot]

I want to have a 425 A-Square Express built. I have some data for the 400gr, but I'm looking for something lighter. I've got my eye on a CEB 257gr Flat Base Raptor.
I know there is at least one other version of 425 Express, but I'm only interested in the A-Square version.
I know the 425 is an oddball, but that's why it appeals to me. my safe is full of oddballs.

Any help would be appreciated
THANX
Curtis

 

[RLL]

Referring to the 300WM case using .423 bullets, for the CEB I would likely start with something like RL10 and see what the results are. RL7 or 4198 could be ideal but may be on the faster side.