I've had two .308's and neither one shot. .30-06's I've had a lot more of and they've been mostly accurate. The two most accurate cartridges that I've experienced in a good representation of rifles have been the .243 and .270 not counting varmint rounds.
Same here. I've also ran into some freakishly accurate 22-250's, 6mm remingtons, and 9.3x62mm's.