Hi Dan, Glock does not recommend shooting +P+ ammo, but that is a recommendation. This ammunition may generate a higher pressure than standard ammunition, which could shorten the life of the parts of your firearm. So if you use it, use it sparingly.
Stay safe & have a great day!

We recommend using ammunition that is manufactured and meets SAAMI or other industry standards, and while some +P ammunition meets these guidelines, +P+ usually does not. This ammunition may generate a higher pressure than standard ammunition, which could shorten the life of the parts of your firearm.