The 7.82 Warbird is a much better cartridge, no useless belt, pointless rounded shoulder angles, shorter case length and optimum case capacity for best velocities with 200 gr and heavier bullets, and is supremely accurate
BUT ... it suffers from highly expensive brass that doesn't last long at peak pressures, same as the 30-378 WBY, you can load both at lower pressures to extend the life of the brass but then the 300 RUM and 300 Norma Mag Imp wildcats come along and stomp on them
I have all three and hunted with them for many years, like them all but the 300 RUM makes the most sense
currently working up a load for the 30-378 with new powders/bullets that weren't available 10 years ago, then gonna play with the 7.82 Warbird again with same