Lots of threads on "best" bolt battle rifle...
But asking which one is more accurate is a waste of time. ALL the old rifles have been to the wars, in one way or another. ALL have had corrosive ammo shot throuogh them. Some have been arsenal redone and sat in warehouses for 40 years or more. Others have not. And, the ammo you use goes a long way to making the rifle accurate.
I have a 1917 SMLE that shoots under 2" @100yds with Remington core-lokt 180gr .303 British. A friend has a No.4 "converted" into a jungle carbine look alike that shoots about 6-8" groups no matter what you stuff it with.
If you take the time and effort to tailor ammo to the rifle (cast bullets sized to the bore, careful load developement, etc.) you can even get rifles with trashed looking bores to shoot reasonably well. But don't expect to pick up any old rifle and some war surplus ammo and have it be a tack driver.
Actual bore size (groove diameter) can vary ALOT on those old guns, and unless you actually measure and match the ammo to it, accuracy is usually only fair. Sometimes you get lucky, but don't expect miracles.
Also, the "accuracy" of the milsurp guns is affected by how well you can shoot them. Some of the sights are pretty good, others not. Triggers run from horrid to great (within the norms of the military two stage pull), and stock fit plays another part.
All in all, each rifle is an individual, and you may find a great looking example that is a poor shooter, or a beat up one that shoots great, and everything inbetween.