How does "temperature sensitivity" manifest itself?

[Captcurt]

Bob Hagel covered this briefly in his book, Game Loads and Practical Ballistics for the American Hunter. He showed several different calibers with 3 or 4 different powders at temps of -20, 0, 70, and 120 degrees. One load that gives me shivers is a 6MM Rem shooting an 85gr bullet using 45 gr of Win 760. The velocity at -20 was 2978 fps. At 120 it topped out at 3228. The velocity spread was 266 fps. Even the difference from 70 degrees to 120 was 168 fps. That is scary.

 

[bfalcon00]

Because I failed to properly plan I'm just shooting regular extruded single base powders. Imr powders aren't fancy but middle of the road in about every way.

Glad to see I'm not the only one in that boat.

 

[lightman]

The only time I have experienced this was when my favorite 223 load that was comfortable here at home showed pressure signs in the Texas Panhandle.

 

[N555]

Take your gun out shoot it, get the barrel nice and hot. Then put that last shot into battery, let it cook for 3 or 4 minutes, fire it, see where it hits.
My 30-30 will hit 2 to 3 inches high with a hot round at 150yd.
748, 760 and leverevolution are some of the most temperature sensitive powders on the market.
Problem is nitroglycerin goes from, stabile, to unstable to breath on me and I'll explode from between 80F to some where in the one hundred teens, by 120F pure nitroglycerin is ready to explode if you look at it the wrong way. Those powders, 748, 760, leverevolution have a lot of nitroglycerin in them.