Check out this lightweight, inexpensive, and comfortable rail from ALG Defense.
Trijicon TA50 3x24 ACOG With 7.62x39 Reticle: Best AK-47 Optic?
Book Review: Experiment and Trial
Rugged Surge 762 from Silencer Shop
Shooting AMG Lock Stock and Barrel Kit
The Pocket Life Saver from Student of the Gun