There are legal means to do so.
SAP's will not be granted to take rifles to a range to shoot. However. (I have not yet tested this...but the theory sounds OK to me.) However, if you take the gun to a gunsmith to get work done on it, an evaluation, test, repair, valuation for sale, etc, and that gunsmith happens to have a shooting range onsite, I would think that test-firing could be part of the process.
Note, I have not tested that, but it's theoretically one way it could legally be fired.
Alternatively, having a gunshow at a shooting range, and SAP's will be granted for gunshows, well, hey, you're at a range....
I have not tested any of these ideas, and I don't know off the top of my head anywhere that meets the above criteria, but if such a place existed, it might be how this person is shooting his firearm legally.
NS