Pump action rifle and action lock mechanism

What is this patent about?

’187 is related to the field of manually operated firearms, specifically modern sporting rifles that utilize a pump or straight-pull action. In these designs, the bolt carrier must remain securely locked in battery during firing to ensure safety and pressure containment, yet it must be released immediately after discharge to allow the operator to cycle the action. Traditional semi-automatic platforms require significant modification to incorporate a reliable, mechanical action locking mechanism that integrates seamlessly with standard fire control groups.

The underlying idea behind ’187 is to utilize the kinetic energy and rotational movement of the hammer or trigger to mechanically trip a locking lever. By placing a cam directly on the hammer, the act of firing the weapon automatically forces the lock to pivot out of the way of the bolt carrier. This creates a fail-safe synchronization where the action is physically incapable of being opened until the firing cycle has initiated, effectively using the hammer stroke as the signal to unlock the reciprocating assembly.

The claims of ’187 focus on a pivotable action lock body that features a dedicated stop surface for arresting the bolt carrier and a cam surface for receiving input from the fire control group. The independent claims specifically protect the interaction between a cam mounted on the hammer and this lock body, ensuring that the transition from a cocked to a released state translates into a mechanical displacement of the lock. Additionally, the claims require a manual override tab that extends outside the receiver, allowing the user to bypass the lock without pulling the trigger.

In practice, the invention is implemented as a U-shaped component that can be mounted directly onto the existing safety or selector switch pin, minimizing the need for additional receiver holes. A spring, such as a leaf spring integrated into the body, constantly biases the lock upward into a notch or contact surface on the bolt carrier. When the user pulls the trigger, the falling hammer’s cam strikes the lock’s cam surface, rotating the entire unit downward and clearing the path for the bolt carrier to be moved rearward by the fore end grip.

This approach differs from prior art by eliminating complex linkages or gas-operated unlocks, which can be sensitive to ammunition pressure and fouling. By tying the unlocking event to the mechanical rotation of the hammer or trigger, the system ensures high reliability across various ammunition types. Furthermore, the inclusion of external tabs provides an intuitive way for the operator to clear the chamber or open the action for maintenance while the hammer is still cocked, a feature often missing in simplified pump-conversion designs.