Temperature Sensitivity


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Blind Bat
November 29, 2008, 12:47 AM
Sorry for another newbie question. I searched... Once my scale gets here (or if I can borrow one this weekend) I'm going to start working up some 9mm loads using once fired WWB brass, 124gr Rainier plated RN bullets, CCI 500 primers and W231, Titegroup and Unique powders. These are going to be target rounds for use at an indoor range this winter but I'm going to be developing these loads at an outdoor range close to my house until the snow arrives.

Currently it's been hovering in the mid to high 30's during the day. Will a 30-40 degree increase in temperature matter greatly when I switch from the outdoor to the indoor range in either safety or accuracy? Are any of my powders (W231, TG and Unique) particularly sensitive to this type of temp change?


Thanks!

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lgbloader
November 29, 2008, 12:50 AM
Yes, it will... Run for your life!!!!

Just kidding...

Target loads light to mid power should be fine.

LGB

Shoney
November 29, 2008, 03:13 AM
If we are talking 30-40 degree F temp change with 231, I doubt the change will be noticable. If we are talking 30-40 degrees C, you may see a bigger difference.

Where you get noticable changes is with rifle powders, and yes some are more sensative than others. Loads developed at 60-70 degrees F will show marked increases in pressure above 100 degrees F. Conversely, loads developed at that ttemp will show marked differences when fired in sub-zero temps.

In my expereiences with both rifle and pistol, when you get over 100 degrees F and -20 degrees F and lower, strange things happen. At over 100, I have had pressure spikes, and at 40 below. I've had 6MM that normally blew thru deer, stop 3/4 of the way thru the body.

JackOfAllTradesMasterAtNone
November 29, 2008, 03:59 AM
Not a bad newbie question. That means you're thinking. But with target loads for 9mm you've got nothing to worrie about in temperatures that you can stand out in with exposed flesh operating the controls of your pistola.

As Shoney points out, there are certain bottle neck cartridges and the powders for them that can develop some odities with extreme temperature swings. Not to worry with your nine mm though.

-Steve

Blind Bat
November 29, 2008, 04:46 AM
Thanks guys. Just to clarify I was talking in fahrenheit...

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