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Storing Ammo: How Hot Is Too Hot??
Point Blank
Member Posts: 77 ✭✭
I am loading a bunch of 223 ammo and just dumping them into ammo cans.Would storing it where temps would near 85 degree's be ok?? It will be sealed in the cans, so humidity shouldn't be a problem.
Comments
100+ on a regular basis in the summer,and a couple boxes in the truck
where it gets hotter than that!
BW
IT'S WHAT PEOPLE KNOW ABOUT THEMSELVES THAT MAKES THEM AFRAID.
I've never seen any definitive data on the correlation between ambient temperatures and performance of ammunition over time. My WAG is that 85 would be perfectly OK over a moderate length of time - say five years? - but over a longer period would cause a gradual decline in performance.
Bobby, I'd be *real* interested in learning if you have chronographed some of those rounds as loaded and then after a year or two. I've always been told that that sort of treatment - especially the vehicle oven bake - can result in a noticeable drop in velocity fairly quickly.
Interestingly enough, I do have direct anecdotal evidence of the other extreme. Buddy had some ammo he loaded late summer / early fall and we shot quite a bit of it. Come snow fall, he left it in an unheated barn where it was subjected to weeks of sub-zero temperatures, sometimes in the -25 range. The next spring, he took it out to shoot and discovered the report / recoil to be less with a downward shift in point of impact, suggesting degraded performance from the freezing / thawing cycle of daytime / night time temperatures in the cold weather and / or the prolonged exposure to subzero temperatures. There may well have been other factors at work, but this was the only thing we could identify.
where it had gone BLAM in October, it went bang in April and point of impact had shifted downward.
"There is nothing lower than the human race - except the French." (Mark Twain) ". . . And DemoCraps" (me)
While I am not an absolute expert on ammunition and temperature, my experience mirrors the others. I don't advocate high heat for any period of time and I store loaded ammunition in a cool, dark place until needed, same as my powder.
The proof of higher temperatures has comes while shooting prairie dogs in New Mexico in June, midday. Having fired several times, I put the next cartridge in the chamber and then had to wait a brief time until I found the next target. It was in the same zone as the others so I used the same corrections. Bang, bullet hit the hill above and behind the target. I think that the term used now is that the cartridge had time to "cook off" in the chamber, thereby raising the temperature and subsequently the pressure of that cartridge. I now store ammunition in a cooler while in the field and I don't let a cartridge sit in a hot chamber.
This article addresses both heat and cold, going along with what Iconoclast suspicions.
Best.
Some Comments about the Temperature Effect on Ammunition
The initial cartridge temperature can have a decided effect on the pressure (and associated velocity) generated inside a cartridge case when fired. Fortunately, most factory ammunition is loaded conservatively so that little danger will result even under some pretty extremes of temperatures. This temperature effect was demonstrated in the National Match Ammunition of 1930. It seems the ammunition had been exposed to the direct rays of the sun for several hours before the match started. During the match several problems occurred because of excessive pressure. The ammunition had to be withdrawn and replaced with ammunition stored at cooler temperatures. It should be kept in mind that ammunition exposed to the direct rays of the summer sun might reach temperatures much higher than that of the surrounding air. Ammunition temperatures of 130 degrees F or more would not be unusual under such conditions.
At the other extreme is ammunition exposed to very cold temperatures for an extended period of time. Ammunition fired under these conditions may develop inadequate ignition, resulting in low pressure and reduced velocity. While these conditions are not dangerous, it could result in a miss or even a wounded animal for the cold weather hunter. Fortunately, most modern factory ammunition will withstand a pretty good swing in operating temperature before any detrimental effects are noted.
Fig.1 Effect of temperature on pressure for three military cartridges
The Frankford Arsenal and the Burnside Laboratory performed temperature tests on ammunition in the 1930's. It was found that the velocity increase was about 1.7 fps per degree F. The standard temperature was taken at 70 deg. F. Based on this number, ammunition heated from 70 deg. F to 130 deg. F would experience an increase of about 102 fps increase in velocity.
In a similar study the U. S. Ordnance Department determined the effect of cartridge temperature on pressure using ammunition loaded with three types of military rifle powder. The results of this study are shown in Figure1. Note that the cartridge loaded with du Pont 1489 powder showed an increase in pressure of about 5,500 psi for the temperature range of 70 deg. F to 140 deg. F. This is about a 11% increase in pressure and could cause problems in some rifles. Lesson ... keep your ammunition out of the hot summer sun or confined spaces in the summer time.
In a related subject, what happens when ammunition is exposed to very high temperatures generated by a fire? If you were a fan of the old western movies, do you remember how a handful of cartridges, dumped into a campfire by the bad guy, had everybody running for cover with cartridges exploding and bullets whizzing around and ricocheting off rocks and nearby trees? Well, fortunately this happened only in the movies. Tests performed by the Sporting Arms and Ammunition Manufacturers Institute have shown that cartridges exposed to a fire will not explode simultaneously, but rather piece by piece; that the bullets are not projected with any great velocity; and that the material of which the cartridges are made of will usually fly no more than a few feet. In one test both rifle and pistol cartridges were stood up in the bottom of an electric lead melting pot. A piece of corrugated cardboard was placed over the top of the pot and the heat was turned on. When the cartridges exploded in no case did the bullets pierce the cardboard or even dent it deeply. While I don't recommend standing around a fire and watching a batch of ammunition cook off, the danger is much less than most people have been led to believe.
And from the Marine Corp:
a. Protection from the Elements. To protect ammunition from direct exposure to snow, leave it in shipping containers until it reaches its intended weapon systems. Dumps should include cover over ammunition and keep stored ammunition 4-6" off the deck.
b. Gunline Storage Sites. The mishandling of ammunition or improper storage at the weapons site causes most misfires. Store ammunition at the same temperature as the gun and protect from the weather.
c. Freeze/Thaw Periods. Awareness of the effects of probable freeze/thaw periods is essential for proper storage procedures. Keep ammunition out of low-lying areas. As a result of thawing and freezing, the area could flood during the day and freeze solid at night.
http://www.tpub.com/content/USMC/mcr3351a/css/mcr3351a_70.htm
And from the Army:
Effects of Temperature
Effects of temperature Temperature affects the firer, ammunition, and air density. When ammunition sits in direct sunlight, the burn rate of powder is increased, resulting in greater muzzle velocity and a higher point of impact. A general rule is that when a rifle is zeroed, a 20 degree increase in temperature will raise the point of impact by 1 MOA. A 20 degree decrease in temperature will drop the bullet 1 MOA. The key is consistency in shooting environments or knowing how the changes effect your shots when the consistency is off.
it's not the type of gun you have in the heat of a battle that counts, only if you have enough ammo for it, lets face it, a gun without ammo is only as good as a base ball bat!!
former air operations officer SEAL Delivery Vehicle Team 2. former navy skeet team, navy rifle/pistol team member. co-owner skeetmaster tubes inc.. owner/operator professional shooting instruction.
Former Member U.S. Navy Shooting Team
Former NSSA All American
Navy Distinguished Pistol Shot
MO, CT, VA.
I carry my 1911 with me, sometimes having to leave it locked in a compartment of my trunk, and the temps in Louisiana have a tendency to be quite warm in the summer. Not wanting to be in a life and death situation with 'old' ammo, I expend it downrange and replace it as it is used up.
I guess that I just like the idea of having relatively 'fresh' ammo on hand at all times. And it gives me a good excuse with the wife to get out and go shooting on a frequent basis. [:D][:D]
John
A friend will post your bail. A good friend will be sitting next to you in the cell saying, "man that was fun!"
We also had to do "explosion" tests (because of the experimental nature of these rounds) for the Depart of Trans. We actually had to drill holes in the second and successive rounds to get them to explode. So, highly unlikely you could get a batch to "Blow up". Even in fires, as was mentioned...not much goes on.
Spie
Good judgement comes from experience.
Experience comes from bad judgement. Gen. Omar Bradley