Component parts for guns; Tools specially adapted for adjusting firearms, namely, barrel wrenches; Firearm attachments, namely, modular external rail systems for attaching accessories to firearms; Firearm attachments, namely, modular external rail systems for firearms; Firearm attachments, namely, mounts for attaching accessories to a firearm; Firearm attachments, namely, mounts for attaching ancillary equipment to a firearm; Gun stocks and chassis