Aero Precision .308 BAR Shim Pack Stainless. 308 BAR Shim Pack. These Rifle Parts by Aero Precision are easy to install and can be installed in seconds so you don't waste any time fitting your barrel. However these Aero Precision .308 BAR Shims are essential when using an AR-15 barrel because they add a little extra "insurance". These Aero Precision .308 Bar Shims help to prevent an unlevel shooting surface which can put marks on your target. They also act as a form of insurance to protect your rifle and are included when you purchase their M5E1 Handguard Barrel Nut. Get your Aero Precision .308 BAR Shims today to properly install BARs onto your bolt-action rifle. Specifications for Aero Precision .308 BAR Shim Pack: Manufacturer: Aero Precision Condition: New Color: Stainless Quantity: 1 Country of Origin: USA Package Contents: Aero Precision .308 BAR Shim Pack Aero Precision APRH308950C: .308 BAR Shim Pack Stainless