The Heym SR30 is a modern hunting rifle produced in Thuringia, Germany using a rather clever and interesting locking system. It is a straight-pull rifle with six ball bearings around the circumference of the bolt head. When the bolt handle it forward, it forces a central plunger down the interior of the bolt body, forcing the ball bearing out to lock into recesses in the receiver. Pull the bolt handle back, and the plunger retracts, allowing the locking bearing to retract into the bolt so it can open. This avoids the usual problem of straight pull systems having quite stiff actions when a camping system is used to translate linear motion of the bolt handle into rotary motion of the bolt head.