Here's one from Eagle. Link--> Eagle Industries*::*Cases*::*Sniper*::*Shooter's Stock Pack Rifle
The Shooter's Stock Pack is the perfect accessory for the competitive shooter or hunter who wants instant access to extra ammunition and other miscellaneous items. The Stock Pack also provides a padded cheek weld that adds comfort and lessens recoil.
• Non-slip suede cheek pad for "Proper Cheek Weld".
• 1-1/2" wide, heavy elastic webbing holds your rifle cartridges firmly in place.
• Heavy Duty #9 YKK® zippered Cordura® nylon compartment for miscellaneous items or additional ammo.
• All seams are double stitched.
• 3 Velcro® adjustable tension straps wrap around the stock and hold the pack securely in place.
• Made in the USA
• Lifetime Guarantee