temp sensitivity IMR vs Hodgdon Extreme??
- Thread starter cowpoke
- Start date
dan newberry
New member
the Hodgdon versions are more temperature stable... Varget seems to be the best of Hodgdon's extreme powders for behaving in various temperatures.
What is generally not discussed or pointed out is the fact that the degree to which any powder is--or is not--temperature sensitive has much to do with the particular cartridge, and the load density of the individual recipe...
...in other words, a guy uses W748 in his .308 Winchester load. He says "this is a really temperature sensitive powder because it dropped 100 fps from 70 degrees to 32 degrees."
But another guy doesn't find that to be quite the case. The velocity only drops on his .308 loads 40 fps. Why? It's the particular load recipe he's using; it has greater load density, and is perhaps deeper into an accuracy node than the other load.
But again, the short answer to you question is that Hodgdon's "extreme" rated powders are more temperature change resistant than their IMR counterparts.
An in my opinion, other things equal, IMR's powders are a bit more accurate, giving tighter extreme spreads of velocity possibly due to lighting more easily than the coated granules in the extreme series of powders.
Dan
What is generally not discussed or pointed out is the fact that the degree to which any powder is--or is not--temperature sensitive has much to do with the particular cartridge, and the load density of the individual recipe...
...in other words, a guy uses W748 in his .308 Winchester load. He says "this is a really temperature sensitive powder because it dropped 100 fps from 70 degrees to 32 degrees."
But another guy doesn't find that to be quite the case. The velocity only drops on his .308 loads 40 fps. Why? It's the particular load recipe he's using; it has greater load density, and is perhaps deeper into an accuracy node than the other load.
But again, the short answer to you question is that Hodgdon's "extreme" rated powders are more temperature change resistant than their IMR counterparts.
An in my opinion, other things equal, IMR's powders are a bit more accurate, giving tighter extreme spreads of velocity possibly due to lighting more easily than the coated granules in the extreme series of powders.
Dan
CatShooter
New member
Originally Posted By: cowpokeSorry if this has been ground into the pavement before, I was unable to find it via search.
In general how do the IMR versions compare to their Hodgdon counterparts regarding temperature sensitivity?
Somewhat different, or way way different?
thanks
The temperature stability is determined by the nitroglycerin content. Standard ball powders like W-748, H-335, H-380, etc are the worst. Heavy loads developed in the spring, can lock up a rifle in the summer - and point of impact will change through out the seasons.
Alliant RL stick powders also contain a fair amount of nitroglycerin, and suffer the same problems.
Stick powders that don't contain nitroglycerin are very temperature stable. The extreme line had deterrents that add a little to stability.
The newer IMR powders are as stable as the Hodgdon Extreme powders.
The temperature stability has nothing to do with the caliber, or the load density.
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In general how do the IMR versions compare to their Hodgdon counterparts regarding temperature sensitivity?
Somewhat different, or way way different?
thanks
The temperature stability is determined by the nitroglycerin content. Standard ball powders like W-748, H-335, H-380, etc are the worst. Heavy loads developed in the spring, can lock up a rifle in the summer - and point of impact will change through out the seasons.
Alliant RL stick powders also contain a fair amount of nitroglycerin, and suffer the same problems.
Stick powders that don't contain nitroglycerin are very temperature stable. The extreme line had deterrents that add a little to stability.
The newer IMR powders are as stable as the Hodgdon Extreme powders.
The temperature stability has nothing to do with the caliber, or the load density.
.
CatShooter
New member
Originally Posted By: cowpokeHi Catshooter,
when you say newer IMR powders, do you mean that IMR changed the recipe some to make their powders more stable than they were, or do you mean particular ones?
Thanks
Well... both.
They are bringing in some new ones, like IMR 8208 XBR, which is outstanding, and is the new "wuv" of the benchrest folks, and long range varmint shooters. The "burn rate" is roughly equal to 4895, and granule size is tiny so it flows through a measure almost like ball, and you can throw match laods without weighing them - it is in a very useful place on the burn chart.
And I remember using the original IMR powders that were black and shiny from the graphited deterrent - and then, some years ago, I bought a can of one of the classics (probably 4895) and was shocked to see green granules come out of the can. That was the beginning... but no one spoke about temperature stability until Hodgdon started talking about it. I think it is a good move on the part of the powder makers.
.
when you say newer IMR powders, do you mean that IMR changed the recipe some to make their powders more stable than they were, or do you mean particular ones?
Thanks
Well... both.
They are bringing in some new ones, like IMR 8208 XBR, which is outstanding, and is the new "wuv" of the benchrest folks, and long range varmint shooters. The "burn rate" is roughly equal to 4895, and granule size is tiny so it flows through a measure almost like ball, and you can throw match laods without weighing them - it is in a very useful place on the burn chart.
And I remember using the original IMR powders that were black and shiny from the graphited deterrent - and then, some years ago, I bought a can of one of the classics (probably 4895) and was shocked to see green granules come out of the can. That was the beginning... but no one spoke about temperature stability until Hodgdon started talking about it. I think it is a good move on the part of the powder makers.
.
Widow maker 223
Active member
Cat i know you have burned many different types of powder. Have you noticed the temp stable powders burning cleaner than traditional powders.
CatShooter
New member
Originally Posted By: Widow maker 223Cat i know you have burned many different types of powder. Have you noticed the temp stable powders burning cleaner than traditional powders.
Yes... ball powder is the dirtiest, along with the Alliant stuff which is pig dirty.
The new, green, IMR and the Hodgdon powders are a joy to clean up, and they don't leave a lot of crud in gas tubes if you pick the right burning speed.
.
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Yes... ball powder is the dirtiest, along with the Alliant stuff which is pig dirty.
The new, green, IMR and the Hodgdon powders are a joy to clean up, and they don't leave a lot of crud in gas tubes if you pick the right burning speed.
.
.
CatShooter
New member
Originally Posted By: cowpokeare there new formulations of 4064, 4350, 4831, and some of those too?
The "Formula" for single base powders is pretty much the same.
What makes 4064 different from 4350 is the grain size and other really minor stuff like any deterrent's added, or physical stuff like perforations in the grain.
They don't really change that much, and if you took black shinny 4064 from 50 years ago, and compared it with today's green 4064, you would find that they load the same, even though they look real different.
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The "Formula" for single base powders is pretty much the same.
What makes 4064 different from 4350 is the grain size and other really minor stuff like any deterrent's added, or physical stuff like perforations in the grain.
They don't really change that much, and if you took black shinny 4064 from 50 years ago, and compared it with today's green 4064, you would find that they load the same, even though they look real different.
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Widow maker 223
Active member
"Yes... ball powder is the dirtiest, along with the Alliant stuff which is pig dirty.
The new, green, IMR and the Hodgdon powders are a joy to clean up, and they don't leave a lot of crud in gas tubes if you pick the right burning speed."
Iv Noticed the same. I burn a lot of benchmark and varget, runs clean. Tried 748 one time didnt like that stuff.
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Tim Neitzke
New member
Dirty burn is more of a problem with ARs than bolt guns ,is it not ?
dan newberry
New member
here's some info from Ramshot's (Accurate's) website regarding temperature sensitivity, and factors affecting how temp sensitive you'll find a powder to be in a particular application... http://www.ramshot.com/faq/
Most of our powders are not insensitive, and will show some effect at hot and cold temperatures.
However, we test at -40F and +125F and the deviation in most cases are ca 3% to 5% at these extreme levels. Therefore most shooters do not notice much difference under normal practical hunting conditions.
More elaboration on the subject:
Complete temperature stability can only be achieved with tubular extruded powders designs, either with double base (NG) and/or with other coating technologies.
Because the ballistic performance at extreme temperature is completely dependant on the specific combination, it is very difficult to quantify and qualify.
Our standard powders perform very well at extreme temperatures, and usually pass the strict military requirements by a large margin.
This is a subject that is often fraught with misconceptions and inaccuracies.
The term is used loosely by manufacturers without qualifying the subject, and is obviously exploited for marketing purposes and perceptions.
The facts are:
Although powders can be improved, it’s really only possible with advanced coating procedures and additives which increase the cost.
A particular powder can be improved re temperature stability for certain combinations, within a certain envelope which is specific to the following three main parameters/aspects
The caliber.
The weight of the projectile/bullet.
The performance level.
If any of these parameters/aspects go beyond or outside the intended ratio/s, the results will change and the performance will sometimes be different.
It is also very important that when a comparison is made, that all conditions re weapon i.e. components primer, case, bullet and the velocity are equal, and preferably done at the same time on the same day.
Most of our powders are not insensitive, and will show some effect at hot and cold temperatures.
However, we test at -40F and +125F and the deviation in most cases are ca 3% to 5% at these extreme levels. Therefore most shooters do not notice much difference under normal practical hunting conditions.
More elaboration on the subject:
Complete temperature stability can only be achieved with tubular extruded powders designs, either with double base (NG) and/or with other coating technologies.
Because the ballistic performance at extreme temperature is completely dependant on the specific combination, it is very difficult to quantify and qualify.
Our standard powders perform very well at extreme temperatures, and usually pass the strict military requirements by a large margin.
This is a subject that is often fraught with misconceptions and inaccuracies.
The term is used loosely by manufacturers without qualifying the subject, and is obviously exploited for marketing purposes and perceptions.
The facts are:
Although powders can be improved, it’s really only possible with advanced coating procedures and additives which increase the cost.
A particular powder can be improved re temperature stability for certain combinations, within a certain envelope which is specific to the following three main parameters/aspects
The caliber.
The weight of the projectile/bullet.
The performance level.
If any of these parameters/aspects go beyond or outside the intended ratio/s, the results will change and the performance will sometimes be different.
It is also very important that when a comparison is made, that all conditions re weapon i.e. components primer, case, bullet and the velocity are equal, and preferably done at the same time on the same day.
CatShooter
New member
Interesting advertising blurb - about as accurate as a 1,000 others.
CatShooter
New member
Originally Posted By: cowpokeWell
this afternoon I went and picked up some IMR 4064, 4350 and 4320 for trying out and working up loads.
None of it was green.... all was dark gray color....wonder what is up with that....
Your grey is my green
Don't worry, be happy.
this afternoon I went and picked up some IMR 4064, 4350 and 4320 for trying out and working up loads.
None of it was green.... all was dark gray color....wonder what is up with that....
Your grey is my green
Don't worry, be happy.
Smokeless
New member
Originally Posted By: cowpokeWell
this afternoon I went and picked up some IMR 4064, 4350 and 4320 for trying out and working up loads.
The only other in the IMR line up that you should keep an eye out for is 4007ssc. Burn rate, I believe to be, between 4064 and 4350 but with better velocity and accuracy in the 243 and a few others. 4007ssc meters better than 4350 and 4064 also.
this afternoon I went and picked up some IMR 4064, 4350 and 4320 for trying out and working up loads.
The only other in the IMR line up that you should keep an eye out for is 4007ssc. Burn rate, I believe to be, between 4064 and 4350 but with better velocity and accuracy in the 243 and a few others. 4007ssc meters better than 4350 and 4064 also.
Makes me wonder how in the world we were so successful in the mid to late 70's with all those custom rifles from the costal areas of S. Ca. in the Summer to the high dessert of NV in the winter...
We just killed everything we pointed at...jeez...I just want to puke everytime I read anything about "temp sensitive", learn how to reload for crying out loud! Cold loads vs hot weather loads..you better get your head wrapped around this fact!
Next marketing we are going to read is NON temp sensitive primers or even better, "temp sensitive brand of cases". What is the dumb [beeep] public going to buy into next...perhaps powder that helps copper fouling...well...that has been around for a long time...military uses it!
We just killed everything we pointed at...jeez...I just want to puke everytime I read anything about "temp sensitive", learn how to reload for crying out loud! Cold loads vs hot weather loads..you better get your head wrapped around this fact!
Next marketing we are going to read is NON temp sensitive primers or even better, "temp sensitive brand of cases". What is the dumb [beeep] public going to buy into next...perhaps powder that helps copper fouling...well...that has been around for a long time...military uses it!
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ninehorses
New member
CatShooter,
So about how much speed do you loose with a one degree temperature drop? I always guessed around one foot per second for each degree, but some powders have been more than this, like a 30 degree drop in temperature, would loose me over 100 fps.
So about how much speed do you loose with a one degree temperature drop? I always guessed around one foot per second for each degree, but some powders have been more than this, like a 30 degree drop in temperature, would loose me over 100 fps.