Temperature sensitivity

ligonierbill · March 28, 2010, 07:40 AM

I know temperature extremes will affect powder performance, but I heard an interesting opinion at the range yesterday. Working up loads for the .338 with IMR 4350 and Re19, a fellow told me that IMR 4350 was much more sensitive to temperature. Anyone else hear this? We had a nice day in the 60's, and both powders did very well, with a very slight edge in consistency to the IMR.

88KEYS · March 28, 2010, 08:13 AM

I have not used that powder but been loading a long time, have seen stuff over the years on the subject of how temp can effect powder. In most stuff that I recall they address the problem with going with a hotter or lighter primer. The temp changes that effect powder are for the most part extreme, like very hot or below freezing. I know the Military talks about it fighting all over the world.

I also know people that claim you should tip the gun in the air, and then slowly back to get the powder to set more even in the case. This is said to get a better burn, it could be but have not seen many shooters doing this.
The guy could have a point that powder is more sensitive, that could be a fact. I think for most of use the changes would have to be extreme to really have any difference for standard applications.

Just my view!

N.H. Yankee · March 28, 2010, 08:17 AM

I have heard some powders are more temp sensitive and what it means is they will not produce as high a velocity in temperature extremes. I have also heard it may be harder to ignite.

Osageshooter · March 28, 2010, 08:21 AM

I have used a lot of IMR 4350 over the years. It is a favorite. I can't say I have seen inconsistency, but I haven't been looking for it. Usually I load and test that load. Maybe in the summer. Then I do a final site in before hunting, and then take that load hunting. The temperatures may vary during hunting, but usually not all that much. I am not shooting at the range then, but shooting one shot at game. I don't think I ever took a load and compared it in the same gun on a day where the temperature was significantly different from another.

All that said, there is a lot out there about this and it looks to me like there is likely something to it. I have recently bought some H4350 and am working with it. I don't think I will be shy about working up a load IMR for deer hunting and using it if it is the best.

338shooter · March 28, 2010, 10:52 AM

IMR 4350 will give slightly higher pressure and velocity at high ambient temperature and lower pressure and velocity at low temperature. It won't make a huge difference but enough to see on a chronograph. This phenomenon can be reduced by using Hodgdon's Extreme powders.

March 28, 2010, 07:40 AM	#1
ligonierbill Senior Member Join Date: May 20, 2007 Posts: 2,448	Temperature sensitivity I know temperature extremes will affect powder performance, but I heard an interesting opinion at the range yesterday. Working up loads for the .338 with IMR 4350 and Re19, a fellow told me that IMR 4350 was much more sensitive to temperature. Anyone else hear this? We had a nice day in the 60's, and both powders did very well, with a very slight edge in consistency to the IMR.

March 28, 2010, 08:17 AM	#3
N.H. Yankee Senior Member Join Date: October 17, 2004 Location: Rural N.H. Posts: 1,586	I have heard some powders are more temp sensitive and what it means is they will not produce as high a velocity in temperature extremes. I have also heard it may be harder to ignite. __________________ The real danger to America is not abroad but within.. Having an open mind is a good thing, but not so open that your brains fall out! Save America, abort liberalism.

March 28, 2010, 10:52 AM	#5
338shooter Member Join Date: March 20, 2010 Posts: 43	IMR 4350 will give slightly higher pressure and velocity at high ambient temperature and lower pressure and velocity at low temperature. It won't make a huge difference but enough to see on a chronograph. This phenomenon can be reduced by using Hodgdon's Extreme powders. __________________ Rifle Scopes Boresighter

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March 28, 2010, 08:13 AM	#2
88KEYS Senior Member Join Date: January 21, 2010 Posts: 145	I have not used that powder but been loading a long time, have seen stuff over the years on the subject of how temp can effect powder. In most stuff that I recall they address the problem with going with a hotter or lighter primer. The temp changes that effect powder are for the most part extreme, like very hot or below freezing. I know the Military talks about it fighting all over the world. I also know people that claim you should tip the gun in the air, and then slowly back to get the powder to set more even in the case. This is said to get a better burn, it could be but have not seen many shooters doing this. The guy could have a point that powder is more sensitive, that could be a fact. I think for most of use the changes would have to be extreme to really have any difference for standard applications. Just my view!

March 28, 2010, 08:21 AM	#4
Osageshooter Senior Member Join Date: August 27, 2009 Location: Overland Park, Kansas Posts: 179	I have used a lot of IMR 4350 over the years. It is a favorite. I can't say I have seen inconsistency, but I haven't been looking for it. Usually I load and test that load. Maybe in the summer. Then I do a final site in before hunting, and then take that load hunting. The temperatures may vary during hunting, but usually not all that much. I am not shooting at the range then, but shooting one shot at game. I don't think I ever took a load and compared it in the same gun on a day where the temperature was significantly different from another. All that said, there is a lot out there about this and it looks to me like there is likely something to it. I have recently bought some H4350 and am working with it. I don't think I will be shy about working up a load IMR for deer hunting and using it if it is the best.