Gryph,
As Daryl says the spacing at the breech would be the same.
The barrels at the top are tilted slightly away from the camera where the lower set are square on.
The tilting makes the spacing on the top set appear closer than the lower set.
Notice also that the 375 top barrel has a thicker profile than the bottom barrel on the same rifle.
All to do with the adjustable regulation I 'spose but it looks a little strange IMO.
Nice setup though!