A simple ammunition casing resizer helps eliminate the problem of the casing becoming frictionally stuck with the resizing die. The ammunition casing resizer is a table top secured base that has a die plate located above the base with the resizing die removably secured within the die plate. A resizing frame reciprocates in up and down fashion under the guidance of either a manually controlled handle or an electrical motor. A ram is positioned below the resizing die while a push rod is positioned above the die such that the ram and push rod, each attached to the frame, travel in up and down reciprocating lockstep. As the ram travels upwardly, the ram presses a casing into the die for resizing and as the ram travels downwardly, the push rod passes through the top of the die and into the interior of the casing, pushing the casing out of the die.