If you look at it more closely you will see that it is NOT possible to slide the base plate, as it is mechanically interlocked with the magazine body against any movement fore-and-aft, permanently.
The mag can be dismantled in much the same fashion as most early Browning magazines, including that of the M1911, by almost fully depressing the follower, then blocking the spring just below the follower with a pin punch through an inspection hole, then shaking the follower alone back to the top and tilting it to remove it through the space in front of the lips. Restrain the spring when you remove the pin punch!
M
