08-21-2011, 03:41 AM
Magpul's grip core inserts actually are designed to hold these different parts in an elastomer plug that keeps them from rattling at all. The have one that holds a spare bolt and firing pin, one that holds batteries, etc. Also, the VLTOR, LMT SOPMOD, and Magpul ACS stocks have storage tubes within them that are good for certain small parts.
