BRDE AR-15 set up blocks
Rear block keyed to fit barrel extension, timed flat with block.
1" thick 2" x 2" blocks
Includes 4 gas block journal support plates, 3/8" thick
4 bore sizes 0.625, 0.750, 0.875, 0.938
All plates have drilled and tapped hole to secure plate to barrel
Includes two 1/4"-28 x 3/8" long soft point set screws
The set up blocks are a meant for someone with a drill press or milling machine. They are especially useful for gas blocks that are pilot drilled, as you can set up on a drill press table and use the pilot hole to drill the block.