Sorry, I just noticed the mesage you sent just now. I see no problem with retumbo and the 180 in a WBY. The retumbo may be a little slow, but it certainly won't hurt anything. I am a big fan of RL 25 in the WBY. If you end up using light bullets, (165 - 180 class) you may even try RL22. I used that for years before they came out with retumbo and RL 25. Also, back then, I was on to the 180 class bullets. I now shoot 210 and bigger....much better down range performance, and I can use slowere powders.
Again, sorry about taking so long to find this. I "trole" the benchrest sites this time of year. i come here more in the fall of the year....HUNTING SEASON!!!
Thanks,
Tod Soeby