Precision barrels are best described as an inner barrel with a diameter of 6.03mm or less. Precision inner barrels leave better compression, improved accuracy, and during a few cases increase speed . Although precision barrels often require more maintenance and cleaning, they will give your airsoft gun a significantly greater range and improve it’s overall performance. The Modify 6.03mm Hybrid Precision Inner Barrel for Bar10 / VSR10 may be a great upgrade for your Bar10 or VSR10 airsoft precision rifle . it’s constructed completely out of aircraft aluminum alloy to form it extremely lightweight, features a 6.03mm bore for incredible performance, and helps make sure that your shots are as straight at possible.