I've never understood why one cartridge is intrinsically more accurate than another. A cartridge is just a pressure vessel an if all is equal (accurate bullets, accurate powder weight, quality primers, barrel quality, etc., then they should shoot equally well.
I think some are just easier for the average reloader to get accuracy out of.
Personally, I'd ask the question a little differently, and pose it to Mule Deer (and others) who've done objective testing of different cartridges as well as other things that affect accuracy:
What characteristics of cartridges (neck length, ratio of volume to bore size, etc.) seem to make a difference in accuracy?
