An interesting observation: in low light firing, I've always been able to verify the sights in the muzzle flash. As a result, I'd know if my shots were good, picking up any that were necessary. I was unable to do so at this match and was puzzled by that. I shot a Glock 23-C with factory ammo. The flame coming out of the ports was fairly impressive, but the unexpected consequence was that the front sight, sandwiched between the flash coming from the ports and muzzle, was totally obscured to me by the port flash. I could not verify my sights in the muzzle flash as I'd been able to do since the late 70's when I first discovered the technique. As a result, I totally point-shot the dark stage.
So if you choose a ported gun for defense, I suggest either finding a load that has flash supressants, night sights and/or a laser. Then bring it to the Carrygun Match and shoot it!