The majority of 7.62 x 54 Russian load data has been developed for .308 bullets. All the 7.62 x 54 Russian rifles that were manufactured in the US for the Russians use a .308 bore and groove dimensions.
If you have a .311 groove dimension in your rifle, yes, you can use .312 bullets.
We do not include the .311 expander as excess pressures can be generated using a .312 diameter bullet in a .308 grooved rifle. Here is the link to purchase the .311 expander: http://leeprecision.com/ez-x-exp-303-b.html
Shooting .308 diameter bullets will give you satisfactory results as the pressure is sufficient to obturate the .308 diameter bullets to the larger bore. Most people like using the .308 diameter bullets as there is a much larger weight and shape selection.
Had we included the .311 expander, you would have been limited to .311/.312 bullets only.