Your video has been edited in places, we can see this.
The video I have in the stream there is raw footage, no editing at all has been done there (which is also why it's nearly 2 hours long and has random footage of me blowing stuff up :D ).
In the raw footage, you can see the shell de-spawning right above the tank, several times, if it passes us at all any distance, using a HESH round we'd at least see the splash or even the sound of the explosion (my View distance was maxxed out as well).
So to clarify here:
The shells will not go further then 17.1km