I recently bought a Wby MK 5 stainless in 30-378. After lots of accuracy testing with bullets 168-220 grns it wasn't inmpressing me. My question is of what quality is the action and should I use it for a cutom gun in say 30-338 Lapua or even 30-378. I have done a lot of shooting but never ventured into the custom gun building. Any responses would be appreciated.