Those were built off a contract through the Rhodesian army from FN. I cant remember much about it the article I read, but it was in a magazine a bunch of years ago.. Either way, they operate just like an A5. The cyclic rate is very very fast. It was up until the early 90's the fastest cyclic rate auto shotgun available. All those small holes milled/drilled into the reciever are for oiling the gun after you clean it. Just a drop in each one of those holes with do you.
As far as the mag tube cutoff switch.. That is a very neat function. Let me explain... Say you are stalking in the bush for some two legged uppity critters.. All you have in the gun is buckshot.. But you think you may have a nest and need to flush em out.. Switch that lever backward, and you can change/extract the loaded shell, put in say a flechette shell, switch the lever back forward, and shoot on the move.
They will last forever because they were milled out of a solid chunk of steel, so make sure you oil it real good when you clean it.
Other than that, load it up and shoot it!!