New Gun Owners

Is Your Gun Waterproof?

waterproof gun in action

The expression “all skill is in vain when an angel pees in the touch hole of your musket” reflects the inability for guns to function reliably in the rain. This expression was popular up until the 1830s percussion caps.

Fifty years later, cloth machine gun belts would fail when wet, and all the way up to the late 1940s, scopes would fog up from temperature changes.

Today, many guns have become more water-resistant. But just because your gun is modern doesn’t mean it’s waterproof.

So, how well does your gun fare in the rain? Can it survive a dunking should you have to take cover in a water-filled ditch or stumble when crossing a stream?

These are questions to ask yourself when determining whether your gun is waterproof or not.

rain waterproof rifle

Types of Gun-Related Water Problems

The problems posed by rain or standing water range from long-term rust and failure to function to catastrophic blowup on firing. Let’s take a look at three of the most common.

#1: Rust

The first issue may be mitigated with the use of stainless and chemically coated components and plastics, but is only solved with careful maintenance.

Every time a weapon is exposed to condensation, rain or immersion, it should be stripped and dried with water-displacing chemicals, towels and dry air.

#2: Failure to Function

A more immediate problem is the failure to function—due to water collecting in the firing pin channel or interfering with feeding. Clean moisture is one thing, but standing water often deposits grit or silt into the weapon, greatly increasing friction between parts.

The only way to get around this is to prevent immersion or to mitigate the influx of dirt with a plastic or oilcloth wrap. In testing, well-sealed weapons like K98, M16 and G3 have fared much better than the more open designs of the M1 and the M14 type.

Perhaps the most dangerous effect of waterlogging is the capillary action holding water in smaller caliber barrels, such as 5. 56mm.

A bolt-action hunting rifle barrel may well burst if a high-velocity bullet hits incompressible liquid. Opening the bolt and shaking the rifle usually dislodges the water, enabling a safe shot.

#3: Sight Failure

Of separate concern is the failure of sights. Small aperture sights have the same capillary action problem as the small bore barrels. Open sights seldom get waterlogged, and neither do ghost rings.

Most higher-end and mid-grade scopes are entirely waterproof, though they may well rust over time. The same is true of red dot sights, lights and lasers.

The trend towards ergonomically poor membrane buttons has come mainly from the effort to make waterproof devices on a limited budget.

rifle in action

Waterproof Isn’t Fool-Proof

For fair-weather shooting, this is all of minor importance. For use at the dire extremes, or under extreme conditions on a hunt, it would be useful to know just how much your weapon system can take.

With MIL-SPEC guns and accessories, test information is usually publicly available. Unofficial tests are usually available for any sufficiently widespread optic or weapon. Water-resistance is one of the factors separating a $30 “airsoft special” from a $300 optic.

The same waterproofing gaskets also serve to keep out dust, which is an equally potent destroyer of optics.

Keep in mind that, despite internal waterproofing and nitrogen fill, condensation on the outside of objectives can still happen, including frost from the shooter’s careless exhalation in winter. A backup mechanical sight might just save the day in that case.

Is your gun waterproof? Do you have experiences with waterlogged guns? Let us know in the comments below.

About the Author:

Oleg Volk

Oleg Volk is a creative director working mainly in firearms advertising. A great fan of America and the right to bear arms, he uses his photography to support the right of every individual to self-determination and independence. To that end, he is also a big fan of firearms.
The Mission of Cheaper Than Dirt!'s blog, The Shooter's Log, is to provide information—not opinions—to our customers and the shooting community. We want you, our readers, to be able to make informed decisions. The information provided here does not represent the views of Cheaper Than Dirt!

Comments (5)

  1. Interesting overview, one might mention the fact that the Army scrapped the 3-prong flash hider on the M16 service rifle because it sucked water into the barrel by capillary action and caused the rifle to burst it’s barrel. Uncle changed to the 8 slot birdcage flash hider and solved that fighting in the rain problem. Another popular solution was the shoot off muzzle cap, which keeps rain water out of the barrel, and dirt and sand too. The 3-prong flash hiders are popular with manufacturers because they are super easy to make, not because they are better than the GI birdcage flash hider.

    If you think you might have to really depend on your rifle one might try testing it and all your attached accessories by soaking it with a garden hose or dipping into a bath tub or swimming pool.
    Does the plastic stock fill up with water? Does all the water drain out of the action? Is the red dot sight or laser or flashlight still working? Are all those parts really parkerized or just blued sand blasted steel? Did the optics fill up with water or start releasisng bubbles?

    If your just playing commando shooting games at the range during an occasional drizzle what you have might not be too much of a problem, but if your going operational outdoors during the rainy season better check your equipment before skids up.

  2. I love my AK47 for just this reason. It has been tested in water, snow, and mud. Due to it’s open design it clears most of these obstacles easily. Of course it doesn’t hurt to do thorough cleaning after a day with such. When cleaning it is so simple to disassemble and reassemble its enjoyable. I have to admit that there have been times when after a long day, I have not cleaned it. But, it still has never failed me.

  3. Does anyone know how well the spray on waterproof coatings actually work? Or possibly the coating that you can send you gun in to have applied? Sorry, don’t know the name of the products, just know they are out there.

  4. I’m a person who can attest to the need on a good maintance program and waterproofing of firearms. I have a navy colt .36 cal pistol that came in kit form from New Jersy arms in the early 80s. It was manufactured in Italy but was a very good quality reproduction. It actually came with the colt named stamped into it. The brass was rough from casting and wood handel needed to be carved and sanded to finish. I once lost this pistol in a creek for over two weeks. The breakfree clp that I had started using to protect it kept it from rusting. This after at least three chambers had been emptied on that hunt. Ive used this pistol alot, have neglected cleaning it more than once, but the clp has kept it from rusting. It has a couple of very small pits in the bore and a couple of chambers show some pitting in there very bottoms, but really not bad for the times I’ve left it uncleaned for months on end. I live in a humid state and only use real black powder that as we all know is very hydroscopic and extreamly corrosive. Ive seen alot worse on black powder guns that are only a year or two old, or so becouse of no good metal protection. This pistol is the best example of need to protect. A 30$ kit gun thats still vey shootable, looks like new on the outside and very little pitting on the inside due to bad neglect on my part becouse i would get buisy and or lazy and put it’s cleaning off sometimes for months

  5. Well my SIG Romeo 5 is listed as waterproof to one meter…not exactly what I was hoping for but it’ll do. I always like BUIS, even though the MagPul MBUS I have are plastic, not metal like the Pro. Nice to see the AR design is better at water resistant than some, and I was taught the “retract the bolt slightly after crossing the river to break the seal and let the water drain out” move back in ROTC.
    Interesting article and something people don’t think about, especially if out in the woods long term.

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