OK, let me try to answer this one. Especially since ALL of my Glock pistols have exactly the same extended and muzzle-ported Bar-Sto Precision barrels on them. Liked this:
Here we go:
THE NUMBER ONE REASON TO USE A PORTED PISTOL BARREL IS TO SIGNIFICANTLY REDUCE YOUR FRONT SIGHT RECAPTURE TIME BETWEEN RAPIDLY FIRED REPEAT SHOTS!
Second, all powders do NOT, 'flash'...