Oddly enough, I just opened the October 2012 issue of Handloader magazine and found an article on reloading for the 7.92x57 Mauser.
Both test rifles are K98 Mauser actions - one is a sporter, while the other appears to be a military standard.
One load shown is for 250-grain Woodleigh Weldcore bullets, so it would appear that you can go up to that weight bullet in that action.
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.