Steve is right, A. B. Shirokorad's "Entsiklopediya otechestvennoy artilerii" is a must have book if you are interested in Russian artillery, I have a copy and I refer to it all the time.
Another slightly less massive book on Soviet WWII Artillery is
Artillery of the Soviet Union during the Second World War Author: Ivanov Publisher: Publishing House "Neva" Year: 2003 Pages: 67 ISBN: 5-7654-2731 - 6
Its a very modest book in size, but it covers all the Soviet artillery of the Second World War, including antiaircraft and railway artillery, it is illustrated with black and white drawings,one per gun type, and doesn't have any photos. It might be hard to come by unfortunately.
A very good website with Russian artillery in WWII is:
photos and drawings at: