With most of the country at times victim to sudden downpours, the possibility is very real that you could possibly have to shoot in the rain. With that in mind, is your Glock up to watersports? Let's talk about that.
Unless you live in the high western Mojave Desert near Death Valley, and never plan to leave, odds are you may encounter water and still need a gun with you. It rains in most other parts of the country with great regularity. Residents of the Pacific Northwest usually see more than 100-inches of rain per year. Those in Hawaii get even more. Residents in coastal areas (which cover more than half of the US population) see fifty inches or more rain per year-- spending as much as one third of the calendar wondering if an umbrella is needed.
Will the gun handle it?
Short answer-- of course it will. Long answer-- the Glock series of semi-auto pistols were designed from the start as a military combat handgun. Originally sold to the Austrian Army, these guns were crafted to be carried under harsh field conditions including deep snow; after all, it gets cold in Austria! Since the 1980s dozens of militaries and thousands of law enforcement agencies worldwide have adopted these guns. These armies and police forces typically submit firearms to extensive field trials that include torture tests in rain, mud, desert heat, polar ice, and everything else you could imagine.
This video from TNoutdoors9 shows just how well a Glock can run in wet, miserable conditions:
Heck, if I knew it shot that well, I may go out on the next rainy day and get some trigger time of my own in.
(Be sure to check the grooves on the inside of your barrel, clean any water found, and lueb with a light coat of product)
So you shot your G-gun extensively in the rain, carried it to the beach, or took it white water rafting-- now what? While it's not impossible for a Glock to rust-- there are numerous occasions in which these guns are documented to gather light surface oxidation on worn surface parts like the slide serrations, the Tenifer coating largely prevents it. While the Glock has a polymer frame and Tenifer treated slide, which is nearly impervious to rain, and moisture, the gun does have several minor parts that are susceptible to surface rust if exposed to water and salts. These are mainly internal parts and include the springs and trigger bar.
After shooting in wet conditions, go home, safely unload your firearm, and break it down at least to the field strip level. If you can go in more detail than that with confidence, do so. Wipe down all parts with a clean, dry rag. Some recommend using a handheld hair dryer for a few minutes or so to get into places where water may collect that can't otherwise be reached with warm air. Others advocate spraying WD-40 into these areas as the water displacer, (the first two letters of the product's designation) will push water out and then evaporate. Once the water has been removed by any method, be sure to lubricate as you would normally.
Products such as Ballistol, made to emulsify in water and bond to it, turning the water itself into a lubricant, have been used by the US Coast Guard, US Navy SEALS, and others (like the pre-1945 German Army) for just this reason.
You know what they say in the military, "if it aint raining, we aint training"