jfo4- I did some more research and found out the case capacity for the Ruger 416 is only one to two grains less than the Remington version. But the longer Remington case allows bullets to be seated less deeply allowing more useable powder space. You can compare 400gr loads on the Nosler site (
https://www.nosler.com/load-data/caliber-and-cartridge-data.html) between the Ruger and the Remington. You might be able to interpolate some starting loads from comparing this data.
https://www.hodgdonreloading.com/reloading-data-center -Mark&Belle
