Bolts get the nod for accuracy, IMO.
I like single shot rifles, though. I have a single shot bolt 25-20 that's accurate, for a 25-20. Generally speaking, and I do mean general, non-bolt singles have given me less accuracy than similar-priced bolt repeaters.
The worst, and the best, single shot No 1s were a 25-06 a 3/4" inch 5-shot gun, and a No 1 in .243, about a 3" rifle at its best.
I no longer have any centerfire single shots except for a Encore in .223, which is very accurate but with an afermarket barrel. Two .22 rimfire rifles, Martinis, are quite accurate, holding their own with a Volquartzen 10-22. Almost.
