Steve, push the right trigger forward. If that doesn't work you will have to take the right sidelock off to get to the locking mechanism. If it doesn't open by pushing the trigger forward, it is probably unhooked from the trigger and will not retract the locking bolt. The small lever i side the trigger gaurd is used to cock the rifle hammer.Curious about "no markings". Sidelocks should have WH Baker in block letters or cursive or Baker Pat'd