Saw this in a sticky from DocGKR on 5.56 duty loads…
Be sure to watch your ammo storage conditions. Temperatures above 150 deg F will degrade the powder and cause pressure spikes. Hint: Think locked metal conex containers in the mid-east, car trunks in the southern U.S., and storage areas near heaters in the northern U.S. Also be cautions of leaving a round in a very hot chamber; besides the obvious danger of a cook-off, the powder can also be damaged by the heat, leading to dramatically increased pressures when the round is eventually fired.
I have been putting together a get home bag to be kept in my car trunk, and I was planning on keeping 50 to 100 rounds of 9mm and 100 to 200 rounds of .223.
My travels take me all over the US via my car. Any concerns with high summer temps causing damage making the rounds unsafe for use? I’ve never measured, but I would expect summer temps inside the trunk to potentially reach the 150 deg mark.
If it matters, 9mm ammo is Federal and .223 ammo is Black Hills. I was planning on shooting off the storred ammo each year and replacing it.
Just to add to my above post - if high temps are bad for ammo (and I know that it is), perhaps a smarter question I should have asked was…
how quickly does exposure to these high temps degrade the ammo to an unsafe condition, and would longer exposure at slightly less temp be equally bad?
Say… one week at 150 deg or one month at 100 deg.
I understand there are no absolutes, I was just wondering how long I could keep an emergency stash of ammo safely in my car without worry due to temperature.
If it’s months - I don’t need to worry. If it’s weeks, I need to replace it more frequently. If it’s days, I need to make alternate plans.
While not a controlled test I did have six Glock Model-17 magazines fully loaded with Speer 124gr +P Gold Dot H/P’s in the center console of my Ford Explorer for about 5 years. The only protection the magazines had was a zip-lock freezer bag which they were stored in the entire time. Last week I sold the old Explorer and I decided to fire the Gold Dots off to see how they faired after all this time in the truck. I had zero problems as the Glock magazines functioned perfectly and as far as I can tell the accuracy and velocity was normal to what I have experienced with Gold Dots in the past. Now my truck was parked outside the entire 5 years with temperature swings from 15 degrees in the winter to 95 degrees during the summer. Considering the vehicle can add another 50 or so degrees to that summer heat I think the Gold Dot held up very well.
On another note I had buried a sealed PVC tube with a few half boxes of 5.56 and 9mm up at my mountain retreat a while back just to see what would happen if I let it sit in the ground for awhile (There is a thread about it somewhere on this forum) and I plan to dig it up on 12-21-2012 to see how it faired exposed to seasonal temperature changes over the years. The one thing I did was to chronograph and recorded the results of half of each box of 5.56 and 9mm ammunition in a Bushmaster M-4 build and a Glock-17 pistol before I buried the second half in the sealed PVC tube 18 inches into the ground, that way I will know if the buried ammunition degraded or increased in velocity once it is recovered and fired.
As I said this is not a very controled or scientific test of any sort but it will be intresting to see if there is any changes in velocity or condition once I dig up the tube.