A method and apparatus for intentionally slowing the speed at which detachable ammunition magazines can be interchanged in a firearm receiver. A magazine catch assembly includes a latch adapted to engage a recess of a standard magazine in the magazine well. A hand-activated crank interacts with threads of a push-rod portion of the latch so that manual rotation of the hand crank in one direction (e.g., counter-clockwise) displaces the latch after a sufficient number of turns. Reverse rotation of the hand crank returns the latch to its engaged condition ready to automatically re-engage the next magazine inserted into the firearm receiver. Alternatively, viscoelastic foam or other mechanical time-delay feature can be used instead of screw threads to introduce a mechanically transmitted dwell period before the latch is actuated.