So i put a rail for a vertical foregrip on my saiga today.
Got a Cabela's bargain cave MOE rail (ripped package) for $6.89 today, decided to use it on my saiga.
Also had a spare vertical foregrip laying around so i used it.
Popped off the handguards, aligned holes of the rail segment, drilled, dremel'd inside of handguards until the nut would fit, tightened and then mounted vertical foregrip.
solid, easy, and cheap.