Abstract: A rail cover may be snapped on or off the side of Picatinny rail mounted to a weapon, such as a rifle. The rail cover protects the user from the teeth of the rail and from heat generated during repeated firing. The rail cover is readily installed or removed from the side, rather than being slipped over the end of the rail, by pressing it onto the rail or by prying it off the rail. The slightly flexible rail cover is preferably made of a polymer to which a rubberizing agent has been added and by forming grooves in its top surface. In addition to improving flexibility, the grooves also improve the user's grip on the rail cover. Locking tabs on the underside of the rail cover, dimensioned to fit in the grooves between adjacent teeth of the Picatinny rail, prevent axial movement of the rail cover when it is installed.