Chart time under Ater (hours) w tyPe 0 unseAled 4 unseAled 8 unseAled 46 unseAled 46 wAterProoFed h sealed primers and same ammunition wit 5-grain ammunition the sus ver on niti mu 11 ofed am m luger data for non-water pro merged for various times. Factory 9m case mouths, when sub . of water exposed to 13" depth essure (Psi) velocity (FPs) Pr 33,300 1,129 24,900 997 22,200 944 too low to meAsure 515 33,600 1,127 ition ection for ammun and inexpensive. fortunately prot e bl la ai av is readily e long-term and components ainers will provid . Plastic nt co l ina ig or ed e or water tightly capp ants from moistur corrosion-proof. ell op pr r fo n tio protec better and are containers work be impossible for you to tell how much moisture is in the mix. The primer sensitivity and explosive output is strongly determined by it’s moisture content. You really don’t know what you’re going to get trying to dry primers in terms of their output or sensitivity. Never expose even wet primers to any kind of heat source. That’s asking for it. The minute you start disrespecting primers you’re going to get burned, literally. If you have primers that have been exposed to water, I would suggest soaking them in oil or powder solvent to inactivate them and dispose them. Water Pressure The deeper the water the greater the water pressure at the bottom of the water. It’s the effect you feel when you dive to the bottom of the deep end of the pool and you can feel the pressure on your ears. The deeper the water loaded ammunition — or any container it’s stored in — is exposed to, the higher the water pressure, and the more likelihood of water getting into things. Obviously, the longer things are exposed to deep water, there’s more potential for water to seep into things. Deep water, say water measured in feet, will compromise unprotected ammunition very quickly. The easy answer with loose propellant is to store it in the original container with the lid tightly closed. This will provide adequate water protection for short periods of time for anything other than 20' or 30' of water. Propellant is actually manufactured in large kettles — under water. It’s done this way for safety and for the water to provide a means of carrying other chemicals into the grains of nitrocellulose making up the propellant. The propellant is essentially cooked in a water solution with other chemicals at very specific temperatures and lengths of time. This gets the correct chemical composition to maintain the proper performance. After this cooking WWW.AMERICANHANDGUNNER.COM Powder Hates Water phase is done, the propellant grains are dried in temperature- and humidity-controlled cabinets to very exacting amounts of residual moisture. Most propellants are typically dried to about one percent residual moisture and volatiles. The amount of residual moisture and volatiles has a very strong effect on the burn rate of the propellant. Depending on the propellant and the cartridge a one percent change in the residual moisture and volatiles content of a propellant can change the peak pressure from 5,000 to 10,000 psi, either up or down. The higher the moisture content, the slower the burn rate, and the lower the pressure the propellant will produce, and vice versa. The moisture content can eventually get high enough to prevent propellant burning. As a side note, this effect is one of the reasons you don’t want to expose propellant or ammunition to high temperatures for long periods of time. The propellant will dry out and the pressures will go up. The propellant will also start to chemically break down after long-term exposure to heat, driving the pressure even higher. Sometimes dangerously so. Don’t store ammunition in the garage, or your closed car or trunk in the summer. In loaded ammunition there’s a press fit between the primer and the case, and the bullet and the case. This press fit by itself will provide some protection against exposure to moisture and very short durations of being submerged in water. It’s enough to prevent any significant performance degradation from exposure to light rain or dew. By short duration of submersion I mean maybe well less than an hour. The shallower the water, the longer it will take for water to seep into the case. The greater the depth and the longer the exposure, more water will seep into the ammunition. At this point it should be pointed out almost all military spec ammunition is waterproofed and will resist exposure to water quite well. I set up a test to show the effects of water on unprotected ammunition. . The test was very simple, and used nothing more than a 5-gallon plastic paint bucket and tap water. For test ammunition, I used a commercial 9mm 115grain load. The unsealed ammunition was submerged in the bucket of water, and the same type of ammunition, but with the primers and case mouths Continued on page 80 When sealing the primer and case mouth makes certain the sealant goes completely around the primer and mouth. the 9mm cartridge was sealed with finger nail polish and the .40 S&W was sealed with threadlocker. the finger nail polish is much easier to see. Loaded Ammo 55
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