The Sierra Precision Adjustable Buttplate is easy to install in the AR-15, AR-10 and SR-25 rifles.
The buttplate is adjustable for length of pull, vertical position, and cant. Installation is simple - remove the two buttplate screws and the original buttplate, then install the adjustable buttplate using the original screws.
Older buttstock weights may need to be shortened slightly or drilled to provide clearance for the buttplate center bar. The Martin Rifle Buttstock weight has the center bar hole already drilled. Not legal for service rifle competition.
Sinclair, Issue:3B, Page:221
Sinclair, Issue:3B, Page:225