Main Function: to eliminate gap between rail and upper receiver. These washers will ensure a contour fit between barrel nut and upper receiver, eliminating misalignment and RIS instability. The MB Barrel Nut Washers come in 4 sizes to fit many different configurations.

Madbull Barrel Nut Washer (2mm/1mm/0.15mm/0.1mm)
Eliminate gap between rail and upper receiver
Precisely aligns fastening screws on RIS systems
Ensures stability
Prevents RIS from angling during installation

1 x 0.1mm
1 x 0.15mm
1 x 1.5mm
1 x 2mm