Obviously scrap metal military guns as already mentioned like AK's, & SKS's, & the ol 6.5 jap from WW-ll.
As far as modern huntin rifles go IMO, Rem tops the list with some of thier autiloader, & pump "masterpieces".
Rem semi auto 740, 742, & 7400
Rem pump 760, & 7600
Now, of course, there were a few accurate ones made. The sun even shines on a dogs butt sometimes. But as a whole, those were some of the most wildly in-accurate p.o.s. rifles ever assembled. I know, cause I owned one, & know a few other folks that did, or still do too. They're all minute of Volkswagen at 100yds on a good day.
I've hered of a few single shot New England Firearms type rifles that'd give the Rem autos, & pumps a run for thier money in the accuracy (or LACK there of) department tho.
I'm sure every major firearms manufacturer has made some lemons. Some models of some manufacturers rifles are complete hit, or miss too, (some of the Ruger's mentioned in earlier posts) but the Rem's mentioned have been pretty darn consistant in the joke for accuracy race.