This information taken from another reloading forum concerning this same subject (Primer sizes in .475 Linebaugh):
"In a previous column, we talked about some problems in loading, related to primers and the change in specifications to use a large rifle primer. Both Starline and Cor-Bon brass now have a headstamp with “R” to indicate rifle-sized primer pockets. Even though the diameter of large primers is the same for both rifle and pistol the depth of the pocket is not. If you try to put a large rifle primer in a pocket meant for pistol size it’s highly likely the primer will not seat flush with the cartridge rim and this is a recipe for all manner of unpleasantness in a heavy recoiling gun."
As Stimpy said, a call or email to Starline would be in order. www.starlinebrass.com
Bill
EDIT NOTE: The Hornady 6th Edition calls for Large Rifle primers for the .475 Linebaugh.
Checking the height of Large Pistol Primers vs. Large Rifle Primers that I have, there is a difference of .009", with the Large Rifle Primers being taller.