The 6.5x52 uses the standard .257 bullet, not .264. The .25/35 & 6.5x52R are identical, the latter is just the European designation for the cartridge. Last year I put together a Contender Carbine with a custom .25/35 barrel and have been shooting the Sellier & Bellot "6.5x52R" ammo in it with perfect results. I measured the bullet diameter against ".25/35" ammo and they are the same. Sometimes names can get confusing, i.e. .256 Newton is a true 6.5, not a .257.
