I use the Tac ops cheek pad/stock bag
Tactical Operations Ammo Cheek Pad Black*::*Accessories*::*Long Range*::*Tactical Works, Inc.
Very well built quality unit plus you can store 8 bullets with it instead of 5.
I also added a piece of 1" pvc pipe about 7 inches long under it for a raised cheek rest. I cut a 1/4 of it out (so it is shaped like a C instead of a O) then wrapped it in some thin foam and strapped it tight.