does cold affect ammo performances

Still_free

Still_free

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i read an article somewhere that say's that cold temperature doesn't affect neither the ballistic nor the energy upon impact,

i went last year in the north to hunt and i was firing with my 300wm. at -40 the recoil i felt was way lighter than usual, almost like a .308 and the dammage infligted upon a caribou were weird, as if i was shooting at them with a 3030.

so i am wondering is there a difference in the impact if the shells are frozen (my shells were stored in my chest pocket at body temp.) if the bullet is frozen does the lead and copper alloy tend to generate less expansion? if the powder is cold, i know it burn slower but does it reduce the recoil that much? is the energy upon impact that much reduced?

thanks a lot for your anwsers to my inquiries.
 
Don't know where you got the BS info, but it's generally accepted that ammunition is very much affected by temperature, you were not imagining the difference.
Hogdon has a new line of powders that are far less temperature sensitive, if you reload.

As to the bullet reacting differently, I've never seen this tested out, however, it is known that metal parts tend to break much more easily at very cold temperatures, and I suspect that lead would be no different, it's likely way less malleable, and prone to break up.
 
the bullet would probably react the same as in warmer temps because the heat from the burning powder, friction from the barell and air would stop it from getting cold enough to change the molecular structure. Thats my 2c, anyways
 
Still_free said:
i read an article somewhere that say's that cold temperature doesn't affect neither the ballistic nor the energy upon impact,

i went last year in the north to hunt and i was firing with my 300wm. at -40 the recoil i felt was way lighter than usual, almost like a .308 and the dammage infligted upon a caribou were weird, as if i was shooting at them with a 3030.

so i am wondering is there a difference in the impact if the shells are frozen (my shells were stored in my chest pocket at body temp.) if the bullet is frozen does the lead and copper alloy tend to generate less expansion? if the powder is cold, i know it burn slower but does it reduce the recoil that much? is the energy upon impact that much reduced?

thanks a lot for your anwsers to my inquiries.
Click to expand...

The felt recoil may have something to do with the extra clothing you were wearing.
I doubt anyone knows how far a bullet has to travel until its temperature reaches ambient temperature, but I suspect a bullet measuring -40 would behave differently on impact than one measuring +20.
 
Ballistcally there is differences, cold/heat has effect on powder ignition/burn as well as air density changes related to long range ballistics. Don't forget elevation changes if you are shooting somewhere you aren't accustomed to. jetting snow mobiles for temperature is a good example of air density change.

The folks here know what powders the military ammo uses( I don't) and those seem to be less effected by temperature.

just my two pennies!
 
ok thanks, still at 40yards a round of 300wm in the sholder of a caribou didn't do much dammages, the bastard was still runnning away. i had to une an entire box of ammo because the wicked beast was never dead on impact. and i was using fed BTSP 180gr
 
Yes, ammunition and ballistics are affected by temperature/humidity/all non-standard conditions. I won't go into interior/exterior ballistics however general rules of thumb:

1.) Hotter temperatures raise velocities; vice versa for cold temperatures.

2.) Humidity/temperature/non-standard conditions also affect the travel of the projectile to its target.

The so what out of all of this is that when zero your rifle it should be in conditions closest to what you are actually hunting. For guys posting on reloading, you also need to consider the temp when you reload - a good example is if you reload in the winter and develop a load that exceeds max loads from the manual you risk a nice surprise in the summer when the temperature is much warmer and the pressures you are playing with increase.
 
Can't change physic's. Definately will be a difference from shooting in temps of -40 to +40f. How much would depend on the materials used in the ammo's componants.

By some different ammo variations and go to the range and test them in the approximate conditions (temperature wise) that you will be hunting in. If you reload, work up some loads with some different combinations and test fire them under the same temp. conditions also. And try the Hodgins powder.
 
Still_free said:
ok thanks, still at 40yards a round of 300wm in the sholder of a caribou didn't do much dammages, the bastard was still runnning away. i had to une an entire box of ammo because the wicked beast was never dead on impact. and i was using fed BTSP 180gr
Click to expand...

That would be nothing to do with the temperature.
 
Still_free said:
ok thanks, still at 40yards a round of 300wm in the sholder of a caribou didn't do much dammages, the bastard was still runnning away. i had to une an entire box of ammo because the wicked beast was never dead on impact. and i was using fed BTSP 180gr
Click to expand...
No offence but, did you recover the animal to confirm this?

I've been to Inuvik a few times on business,as well as Greenland and Alaska. You would be surprized the numder of local hunters that do very well caribou hunting, using merely 22 magnum, 222 and 30-30 calibre rifles.
 
Higher temperatures will increase the speed and power of detonation.

Great WW2 annecdote that relaes to this. The Candians near Hong Kong were being pounded by the Japanese off shore guns. The Japanese navy knew the capable range of the Canadian guns, so their ships parked just out of range.

The Battery commanders ordered the gundet commanders to build fires using their ammo crates behind each gun position. With the projectiles separated, the gunners would heat the charge inside the brass, keeping it moving to prevent any one spot from overheating and igniting.

Once the charges were heated, the round was quickly reassembld and fired. This gave the Canadian and Brit guns an extra 5 kilometres of range and obviously created a sudden panic for the Japanese ships.
 
You get something like 1fps decrease per degree Fahrenheit downwards, as rough rule of thumb.
To get squib load performance, you are talking about maybe the dark side of the moon.
 
muledeercrazy said:
the bullet would probably react the same as in warmer temps because the heat from the burning powder, friction from the barell and air would stop it from getting cold enough to change the molecular structure. Thats my 2c, anyways
Click to expand...

The friction generated and temps from the burning powder also affect it in regular temperature ranges. Thus they are still -40* lower.
Not to mention that the powder burns less efficiently hence cooler at sub temperatures. Copper/lead bullets and the steel of the barrel also have differing thermal expansion values. (The bullet will shrink more in the cold than the steel barrel will) therefore there will be less friction due to more bore clearance. The air IS more dense so it will increase air friction but in an overall there is less heat generation.
 
Ballistics are affected by EVERYTHING, Latitude, longitude, altitude, temperature, air density, heat, cold, wind, tide (gravity), really, some things obviously have more affect than others. Pilots may be able to chime in and ad more info, or snipers of course.
 
As dizzy said...Ballistics are affected by everything. zwhen yuou use a sophisticated ballistics program, it want's to know everything, and elevation and temperature are key.

Most hunters dont' have to worry to much about it, as the kill zone on animals is large....But if you go from one extreme to another- Check your zero.
 
A typical load may have velocities plus or minus 20fps, so normal randomness is about the same range as a 40 degree F drop.
You can certainly fire one round at one temperature and get a higher velocity than the next round at 20 degrees F warmer. Just due to randomness.
Externally you get more drag in the cold air, plus lower velocity, so more drop. It would get heckish cold before I would notice the recoil difference. Drop and windage would be important, yup.
 
experiment conducted 10-12 years ago.
-20C to +120C. Differences were noticeable but not dangerous. Some powders more sensitive than others.
I'll dig out the data and post it tomorrow. Wish I could post a table here, then I could do it in Excel and it would make more sense.
 
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