I will be getting a new Glock 23 GEN 5 and want to know if the chamber is fully supported on the GEN 5 models. I saw the Buffalo Bore +P 40 S&W ammo and would like to know if this is usable in the Glock 23 GEN 5. In addition, Underwood Ammunition has some extreme penetrator ammo that has no +P designation but I would think these 40 S&W ammos might not work in an unsupported chamber as well. Is there an official +P standard for 40 S&W? If I should upgrade the barrel, what would you recommend?