I will jump in and share my experience with this subject.
I strongly believe that proper gunsmithing is the key to accuracy in any calibre.
If you biuld a big bore rifle with a lightweight taper barrel harmonics will probably
prevent it from shooting very well, but placed on a heavy barrel they will shoot
with any light calibre.
Obviously bench rest shooters don't shoot bigbores because of recoil.
Assuming you could shoot in a vacuum and the quality of all of the components in the
shooting system were best ( barrel,action,gunsmithing,brass,load quality and shooter
skill ) they should shoot as well as small bores.
The reason for going larger for long range is Larger bullets with high Blistic coefficients
are less affected buy external forces (Wind ,humidity,gravity,ETC ).
Heavy bullets tend to have better SD's than light bullets, where as it is tuff to get a light
bullet below a SD of 10.
Also on long range shooting shooter error is magnified .
So I will say there is no reason that a bigbore should shoot any worse than a small bore.
In fact the best group I have ever shot was a .031 and it was with a 400gr 416 bullet
in a heavy ( #8 tapered barrel ) custom rifle
The new army tanks can hit at 4000 yrds and they are realy big bores.
J E CUSTOM