If you watched American Sniper and I am sure you did, you noticed that all the Sniper Rifles had adjustable cheek rests. The use of a cheek rest is vital if your eye does not align with the scope crosshairs when your cheek is on the comb of the rifle. I think that there are also add-on’s on the rest to store extra rounds and sometimes with a zippered pouch such as the Black Hawk Cheek Rest below.
There are lots of cheek rests out there that either velcro on or strap on to your rifle stock. I prefer for hunting a simple pad to lift my cheek without all the other add on’s. Some hunters say that they have lost rounds when busting brush with similar products. But if you are in a tree stand or a blind it works just fine to have rounds that you can access if you like. A great inexpensive Cheek Rest according to buyers is the Voodoo Tactical Adjustable Cheek Rest with Ammo Carrier for 16.00.
IF you are into perfection you can purchase the Bradley Cheek Rest see http://www.bradleycheekrest.com/Bradley-Adjustable_c11.htm Cost is $110-$120 without shipping. Below is a you tube worth watching using this cheek rest on a 338 Lapua Magnum. Of course the .338 has a large muzzle brake too to lessen the recoil, just be sure to wear good hearing and eye protection as these folks do. Honestly I do not own any of these yet but will soon so I have the option to lift my cheek higher if needed.