Dead Air Muzzle Device Shim Kit The Dead Air Muzzle Device Shim Kit offers a simple, precise solution for properly timing your muzzle device. Designed to ensure optimal alignment and performance, the kit includes three clearly marked shim thicknesses to provide flexibility and accuracy during installation. Easy-to-follow instructions are included, with the thickest shim always placed against the barrel shoulder for consistent results. Ideal for achieving correct muzzle device orientation without guesswork, this shim kit makes installation clean, reliable, and repeatable.