The official name of the country was RSFSR. Strictly speaking, there is a small time gap between the October Revolution and the declaration of the RSFSR (and still larger gap to its first Constitution of 1918), which may justify the usage of the term in certain circumstances.
Bolshevist Russia ought to be distinguished from Soviet Russia. While both terms are informal, the latter one has a much wider historical frame. Also, strictly speaking, they differ geographically: in 1917-1922, the Bolsheviks controlled a relatively smaller territory (although gradually expanding) than that of the former Imperial Russia.
The Bolshevik Revolution in Russia in 1917 was initiated by millions of people who would change the history of the world as we know it.
Now that the Bolsheviks had the support of the workers, they were able to win the important elections in early September in important Russian industrial centers.
The Bolshevik leaders felt it was of the utmost importance to act quickly while they had the momentum to do so.