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leaving ammo in car?

ddhotbotddhotbot Member Posts: 1,426 ✭✭✭✭✭
i left some 38 s&w reloads in a baggie on my back seat while i was in the clubhouse talking,maybe 1 hr.when i took them out of the baggie too shoot i noticed how hot the brass was.after shooting them i found pierced and flattened primers.these were a mild load for an old top break pistol.can the excessive heat of being in my car have caused these high pressures? the gun wont lock up tight now either.


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    nononsensenononsense Member Posts: 10,928 ✭✭✭✭
    edited November -1

    "can the excessive heat of being in my car have caused these high pressures?"

    Absolutely! You just had first hand experience with heat gain and ammunition. Never leave ammunition on the seats, in the glove box or worse, on the dash or in the back window of a car. We did some pressure tests doing those same things to rifle ammunition and got 7,500 PSI pressure spikes by direct measurements. If these loads had been at the very top of the pressure curve, we could've had some real damage.

    Your pistol frame is probably stretched and irreparable. But you should take it to a pistolsmith to be sure.

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    stargazerstargazer Member Posts: 6 ✭✭
    edited November -1
    I left my first generation Glock 21 mags loaded in a hot Texas sun in the car while I was doing my CHL classroom. Found out I would be instructed "when " to load the mag by the instructor so on a break I went out that afternoon to unload them. Those 15 year old springs gave it up guys and the rounds just sort of fell out with my range test looming 2 hours from now. The range/shop had just sold all of their Glock 21 mags so the guy at the counter said to leave the mags with him and he would see what he could do. I came out of the class an hour later and he had repaired them by stretching the springs and they had sufficient tension to get me through the range qualification. New mags were on their way the next day! I finally retired those non-drop free magazines for new drop free ones.

    So keep in mind those older automatic magazines too may not can take the heat well either. Check them often.
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    PinheadPinhead Member Posts: 1,485 ✭✭✭✭✭
    edited November -1
    You better believe leaving ammo in a car in hot weather will make the pressure go up. So will laying them in the direct sunlight on a bench during the hot part of summer will do the same thing. I found that out in the summer of 64 when I let some 30/06 loads that were near maximum loaded. I went to the range and set everything up to shoot in my 700 Remington with some well established loads and every charge weighed by hand on scales. I sat and talked for about 20 minutes or better to an older gentleman that was there and just finishing up on his shooting. The first shot out of the barrel flattened and cratered a primer. The second pierced a primer it had also leaked a little around the perimeter of the primer. I quit right then and took everyhting home and pulled down that ammo one cartridge at a time and the charges were still dead on the money. I loaded them back up exactly as I had pulled them down one by one and took them back to the range. This time I left them in an ammo can and shot them one by one. Absolutley no problems. I concluded that the two that I had shot that produced problems were because they had been sitting in the direct hot sunlight for a period of time. AT least that was my experience. Not scientific but I have not left any ammo in the sunlight since and have had no problems since.
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    gotstolefromgotstolefrom Member Posts: 1,479 ✭✭✭✭✭
    edited November -1
    Some facts from another side of this the 'trunk'.
    The town has moved in around me, so I can't shoot from the back porch anymore.

    Lately (last 2 years), at times I would have a chance to do some shooting because of a work schedule change or something, but I couldn't shoot what I didn't have. Sometimes, when in this un-prepared condition, I would shoot the handgun that is always in the car.

    To be prepared for these 'shoots of opportunity' I began to carry one or two guns I would want to shoot, long or handgun, and enough ammo for a casual outing. Most times stored in the 'trunk' created when all the seats of my station-wagon are folded down. I have never measured any temperature differences in the car when left parked for a few hours, but stuff in the light is MUCH hotter than whatever I would pull out from under the folded down seat areas.

    I won't tote my more valuable guns around with me for a week...The guns I'll make available for these 'shoots of opportunity' are usually a favorite mil-surp with mil-surp ammo. Sometimes the ammo will lie in the shade for a while before shooting, but not always. Sometimes ammo is pulled out of the can and loaded into the gun-du-jour. The ammo isn't hot to the touch, or it wouldn't be used just then. The 'trunk area' must not get as hot, but ambient temps are 95+. I can't say if driving with the A/C on while getting to the range changes the temp of the 'under-seat-trunk'.

    I always check spent cases..always. It's either because I'm shooting a recently aquired mil-surp and need to check, or just from habit of 30+ years of reloading curiosity. I've have not noted excessive pressure from ammo shot during these 'shoots of opportunity' over the last few years. No primer 'tells' or other case conditions to indicate un-safe pressures. Certainly no 'shooter noticed' hot ammo.

    You will have to trust me.....I'm not THAT lucky, so I must not be shooting ammo that is 'too hot' (pressure-wise), or has changed dramatically in performance from being in the 'trunk' for the week.

    That's it, just some observations of 'car carry' of firearms and ammo.
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    gunnut505gunnut505 Member Posts: 10,290
    edited November -1
    Another caveat is not to go 4-wheelin' with ammo that's been stored in your vehicle; the powder may have beat itself into a fine powder after about 25 miles, increasing surface area and pressures. Add heat from trunk storage; you may have a problem!
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    bullet makerbullet maker Member Posts: 2 ✭✭
    edited November -1
    So OK, if the temperature makes the ammo, dangerous pressure`s, for being left out in the sun or in a rolled up windows in a hot car, then what about hours later, when the temperature cools off? Like your driving your car with the air conditioner on now, so the ammo has had a chance to cool down. Is it ok to shoot? or is it ruined forever?

    bullet maker[:)]
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    WulfmannWulfmann Member Posts: 4,894 ✭✭✭
    edited November -1
    The type of powder is also a big factor as some are designed to be less affected by heat.
    I have never read anything about Rommel or Monty's boys having to call of a desert fight because they felt their powder was getting too hot.

    However, I have also tried to stay with powders that are known to be safer in temp swings.

    That brings up a good point.
    Is there such a list that categorizes powders as to their heat sensitivity?

    "Fools learn from their own mistakes. I learn from the mistakes of others"
    Otto von Bismarck
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