US Patent 9103625 Firearm with keyhole-shaped mounting points

A firearm with keyhole-shaped rail mounting points has a forend element having an exterior surface and interior surface. The forend element defines a plurality of rail mounting apertures extending from the interior surface to the exterior surface. Each of the apertures has a first portion with a first diameter to closely receive a fastener head of a first diameter. Each of the apertures has a second portion with a second width less than the first diameter size to receive a shank portion of a fastener. There may be a recess on the interior surface size to receive the fastener head, the recess positioned at the second portion.