Ok got it thanks. Just one last question. when they say run some of your carry ammo through your gun what are we really testing there the gun or the magazine? I mean should i run lets say two mags through the gun, same magazine or different one? does it matter?
You're testing the gun for reliability and for accuracy at different ranges. You should use the magazines you intend to use with the gun you carry.
In this way, the gun and the magazines are tested for reliability and you will have some idea where the rounds will impact at different ranges.