Will this test still work if you load a few dummy rounds into an empty mag, or must the magazine be clear of the gun?
This check must be done without a magazine, even using a dummy round the slide is slowed in its last little bit of travel. You need the full impact of the mechanism going into battery for an accurate result.
The most important thing to be learned from those who demand "Equality For All" is that all are not equal...
Gun Control - seeking a Hardware solution for a Software problem...