Ammo and temperature

[hatidua]

Is there any harm in ammo getting really <span style="font-weight: bold">cold</span>?

I keep most of my ammo in metal ammo cans (those used green ones that the surplus stores sell), an additional half dozen cases of .22 are simply in the box that they shipped in (5,000rd case boxes) and keep them on shelves in an unheated garage. It remains relatively cool in there in the Summer but is well below freezing at many times during the Winter. Any input would be appreciated.

 

[ganyana]

Re: Ammo and temperature

Yes... The Biathlon shooters here in Scandinavia use R100 or Norma .22 ammo over Eley...although Eley is generally more accurate in most rifles, Norma 1 or R100 gives more consistent results at any temperature from 0 ºF down due to a bigger priming charge...which is also why they are slightly less accurate at warmer temps!

The Primers Norma uses are all tested at -50ºC (-58 F)...and we have had issues with several makes of primers in the big weatherby cases and similar. Reliably ignighting the charge in a .308 is a whole different ball game to ignighting a .30-378! In fact 1 shot in 50 will blow up a weatherby at -50 with most makes of primers...- the ignition moves the bullet into the bore, and a fraction of a second later the charge really starts to burn...and by then you efectively have a barrel obstuction just in front of the breech.

But...what do you call cold? As soon as the sun rises I'll be trying some new .300 Norma mag loads (thats the .338 Norma necked down) and it is -11ºF. Too cold for me to trust the lead free primers in such a case but ok with most makes of magnum primers...

 

[hatidua]

Re: Ammo and temperature

My concern is more a matter of storage rather than usage: I have no intention of going to the range when it's 0* out.

I would guess that a dozen times a year the interior of the garage gets down into the 10-15* range, and is below freezing (32*F) at night for several months at a minimum.

I simply don't want to be doing long-term damage to a product that isn't free and isn't getting any cheaper as time goes on. I'm lucky enough to have an ammo stash so large that it can't be stored indoors but am worried that might in itself be a problem...

 

[bdh308]

Re: Ammo and temperature

Huh...I think someone should invent the cartridge warmer. Like tire warmers...lol. Hell it probably has been invented.

On a serious note though...I would probably just find somewhere safe in the house to keep your ammo just for piece of mind. I wouldnt think you would want your powder to go through different temp variations that could give us another excuse as is to why our groups had an extreme spread.

 

[ganyana]

Re: Ammo and temperature

In theory, the problem with stored ammo below 32F is that it dried the powder charge out over a number of years. That is the theory....We hold a test batch of ammo (civilian standard- primers not sealed in with laquer) which is just stored..today it is -11f...and the ammo sits there. Every five years we fire a few to check rate of detierioration...

Lets just say that in practice, damp is the enemy not cold, and any ammo made since 1930 will be fine if it has been stored in the freezer.

 

[Switchblade]

Re: Ammo and temperature

My ammunition spent a few years in the garage at temps that ran as far down as -80F during the winter. It all shot fine, and from my experience shooting in wicked cold weather, a warm chamber makes for a really nice cartridge warmer. At first I thought there was an issue as the sound of a firing cartridge was very subdued as if a weak can were being used but velocity checks showed standard velocities. POI/POA was fine.
I use plastic boxes and ammo cans with a bag of dessicant inside of it. Unless you are sitting in minus temps the entire year I do not see any issue with the low temps you are discussing here.

 

[hatidua]

Re: Ammo and temperature

Thanks for the input, I have no desire to ever experience -80*F......ever!

 

[MountainMan2]

Re: Ammo and temperature

I read an article about moisture caused by temp changes. Cold at night and hot in the day. It claimed that the temp changes would cause moisture and the moisture would eventually ruin the ammo. Extreme cold/hot not really being a problem but the change back and forth between the two. Seems reasonable but I don't know how long it would take to cause a problem?