Ok, here's another thing to think about

I'm loading out in my garage, usually after midnight, it's 24 degrees in the garage, most have been done below 40F, how does this factor in if I load some and don't fire them til later like 65F in Kodiak summer?

I figured it was a non issue until reading past threads in HDLG forum there are mentions of temp sensitivity,but realizing most guys are loading inside at room temp and then taking them outside to fire in winter at the range, 25F or lower for you northern guys, then hunting in Fall temps all over the place in this state.

Thinking Brass changes major with temp, are there Sizing Issues, etc?

2. My understanding is the "Temp. Sensitive" deals with the temp. when you shoot it, not when you load it. I forgot the name of this, but: for a given volume of gas, if you increase the temp. you increase the pressure. When you pull the trigger, the powder burns, turns to gas and expands. MAYBE if you work up a Max. load at 10 F. and then shoot that same load at 100 F. you MIGHT get excessive pressure. Some powders are more "Temp. Sensitive" that others.

3. noble gas law. it is "ideal" meaning in reality things don't quite work that way but pretty close. probably there is more variability in how you shoot in different temps. versus how the bullet does if loaded in different temps...

I don't think the temperature while loading is important (as previous guy mentioned it's temp sensitivity when firing) because the rate of expansion/contraction for the brass, copper, lead, etc. will stay the same (proportionally) as your load warms up, cools down, etc.

Of concern is having the temp of bullet and cartridge the same when loading, other than that I don't see where any concern comes from.

So if concerned don't bring warm bullets into a cold garage and immediately load them into cold brass. let all components acclimate before loading and don't worry about it. at least that's my thinking.

4. I would guess with a sizing die at 25* it's possible that it could be sizing your brass small. Then there are the condensation issues that could pop up if you have worm stuff in the cold or bring cold stuff in the worm. But other than that I don't see how it would matter.

5. Don't worry about the loading temp, The only trouble would be condensation of cold stuff brought insde before assembling. Some powders react to warmer temperatures of the round when it is fired. I fired a string of about 10 rounds with a 25/20 fairly rapidly and the velocity rose stedily as the barrel warmed up. After cooling the velocity dropped back to the first round. When the barrel was still warm, I loaded and fired a few quickly and a few I left in the chamber for about 15 seconds before firing. There was about 100 fps difference between the warm rounds vs the cold ones. Many of the newer powders are supposed to be less sensitive to temp.

6. Originally Posted by LeonardC
My understanding is the "Temp. Sensitive" deals with the temp. when you shoot it, not when you load it. I forgot the name of this, but: for a given volume of gas, if you increase the temp. you increase the pressure. When you pull the trigger, the powder burns, turns to gas and expands. WHEN you work up a Max. load at 10 F. and then shoot that same load at 100 F. you WILL get excessive pressure. Some powders are more "Temp. Sensitive" that others.
There (in bold); fixed it for you.

With the preoccupation/fixation on max loads, it will be a certainty to encounter excessive pressures at higher temps, especially in the above. This is the reason chronographs and pressure testing equipment are made, and reloading manuals are written; to keep the idiots from blowing themselves, and bystanders, up.

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