dreadpirate
Ultimate Member
In the days of A2 stocks, there were ( lead ? Steel ?) weights made to fit the compartment .
I believe national match AR's still use weights in the A2 butt stock. See "DCM Rear Balance Wedge, 3.5 pounds" at this link:
https://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_ID=1375