Forward Controls Design Nautilus Variable Timing System NVTS - 1/2 x 28 TPI

The Nautilus Variable Timing System is another excellent product put out by Forward Controls Design.  Replacing stacked shims for timing muzzle devices, the strong two-piece NVTS utilizes interlocking rings to create 12 indexable points for timing your muzzle devices.  

For detailed instructions, watch here on Youtube.