WHAT DOES 18.5″ BARREL MEAN?

So after a several months of possessing this firearm, I've just one huge concern to answer. Could it be nearly as good since the SP5K and which one would I like? In the past, I’ve shot both equally a fair bit and don’t get me Completely wrong, I absolutely appreciate my SP5K, though the Considerably lessen price of this AP5-P coupled with the o