Temperature sensativity of CFE 223

[jamesh]

I'm curious if anyone has any experience with how temperature sensitive CFE 223 is.

 

[Uncle Ed]

The number to the right of the powder is the fps change for each degree of temp change.

 

[jamesh]

Thanks Uncle Ed. I had not seen this chart before. I'm really surprised at the 4831SC number.

 

[SSL]

I've not made a serious effort to chronograph my loads in extreme temperature conditions, but I do know that there seems to be minimal, if any at all, differences in group size from say 80 degrees down to 30 degrees in my rifles. Much colder, I'm too much of a wuss to go through all the fuss of choronographing. I use it exclusively in my .17 Remington and .22-250 and did use it in .223 for a while. It is easily the most accurate powder I've used with my bullet selection in the .17 and .22-250 and acceptable in the .223 (but not quite perfect) while giving top velocity with out maxing loads. As a bonus, copper fouling is minimal (based on accuracy deterioration and cleaning patches) in my specific rifles. No going to guarantee that in others.
If you Google "CFE223 temperature sensitivity" you will find opinions all over the board. Just like with anything else, real-life experiences vary.

 

[SSL]

The number to the right of the powder is the fps change for each degree of temp change.

Many thanks, Uncle Ed. I was typing as you posted and missed that. Great info to have.

 

[Milo 2.0]

I developed a load with CFE 223 in a Dasher, 105 hybrid. It was 90deg when I did the load, loved it, we were going to hunt with the rifle. But a 40-45 deg drop in temps resulted in a 45-50fps loss in velocity.
Not saying this is the norm, but because it was a youth shooting it, I wasn't going to live with the results and switched powders.

 

[Uncle Ed]

Many thanks, Uncle Ed. I was typing as you posted and missed that. Great info to have.

Our military changed powders in their long range 7.62 sniper ammunition from the "double base" RL15 to the single base IMR 4064. And this was because of the wide temperature swings in Iraq and Afganistan. Double base powders are more sensitive to temp changes than single base powders and the chart above shows this.

 

[ricco1949]

Uncle Ed:
Do you know the source of the chart?

 

[Nick Caprinolo]

The number to the right of the powder is the fps change for each degree of temp change.

Ed, can you tell me where you obtained this chart. I suspect there is some additional literature to go with it.

 

[Uncle Ed]

I have no further information on the chart and the chart was all that was posted in another forum.

 

[dmoran]

@jamesh
That chart is tainted data from what I see.
Examples: look at the VihtaVouri N140 to N560
N550 & N560 (both Double-base) less sensitive then the 100-series? ... Not
N140 roughly 65% less sensitive then N150 & N160? ... Not
Or how about RL15 being more sensitive then RL17? ... Not (+20% less then RL17 in my own tests)

 

[Brians356]

@jamesh
That chart is tainted data from what I see.
Examples: look at the VihtaVouri N140 to N560
N550 & N560 (both Double-base) less sensitive then the 100-series? ... Not
N140 roughly 65% less sensitive then N150 & N160? ... Not
Or how about RL15 being more sensitive then RL17? ... Not (+20% less then RL17 in my own tests)

Unless and until I know the source and methodology behind that chart, it might as well be in hieroglyphs.
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[Ned Ludd]

I downloaded a similar Powder Temperature Sensitivity Word file from Sniper's Hide a few years back. My recollection is that the person that posted it claimed it was a compilation of actual temperature data that he and a bunch of friends had generated over they years, something like that. I've looked at it a few times over the years, but without really knowing the specifics behind it or the accuracy of the information it contains, it's of little real value. Needless to say, I don't re-post on shooting forums like this because the there will always be a few people that will believe every single number on it is written in stone, and re-post all over the internet.

Unsupported and undocumented data is kind of like magic. We might really want to believe it's true, but unfortunately, it isn't.

 

[Uncle Ed]

And the window stickers of new cars has EPA gas mileage estimates that can vary from actual gas mileage figures.

But the EPA estimates can still be used for comparisons between other models.

So if any of you can provide better data please do so.

The problem here is some of you people would complain and bitch if they hung you with a new rope.

 

[Brians356]

I downloaded a similar Powder Temperature Sensitivity Word file from Sniper's Hide a few years back. My recollection is that the person that posted it claimed it was a compilation of actual temperature data that he and a bunch of friends had generated over they years, something like that. I've looked at it a few times over the years, but without really knowing the specifics behind it or the accuracy of the information it contains, it's of little real value. Needless to say, I don't re-post on shooting forums like this because the there will always be a few people that will believe every single number on it is written in stone, and re-post all over the internet.

Unsupported and undocumented data is kind of like magic. We might really want to believe it's true, but unfortunately, it isn't.

"Fake News" as it were? That's the one commodity we already have a surplus of.

(No disrespect to Uncle Ed who posted the chart here, it's a reference in its way, but YMMV as always.)
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[Uncle Ed]

"Fake News" as it were? That's the one commodity we already have a surplus of.

(No disrespect to Uncle Ed who posted the chart here, it's a reference in its way, but YYMV as always.)
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I'm sorry, due to the Government shutdown I was unable to get the new relaxed EPA standards for temp sensitivity.

 

[Had2muchofForums]

I did my own testing and found CFE223 to have a 0.25 fps change per degree (F). I have no data to show you and I can't describe my testing methodology and I can't give any other details, but you should believe me because I said so and I posted it online.

 

[Uncle Ed]

I did my own testing and found CFE223 to have a 0.25 fps change per degree (F). I have no data to show you and I can't describe my testing methodology and I can't give any other details, but you should believe me because I said so and I posted it online.

I'm guessing but you also probably drank so much Olympia beer you actually saw Bigfoot.

 

[Ned Ludd]

"Fake News" as it were? That's the one commodity we already have a surplus of.

(No disrespect to Uncle Ed who posted the chart here, it's a reference in its way, but YMMV as always.)
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I don't know that I'd call it fake news...it may well have been really good data from whomever collected it. We just have no way of knowing one way or the other. So as I mentioned, I look at the numbers in file I downloaded from time to time for reference purposes, but I take them with a large grain of salt. In general, they follow the temperature-sensitivity trend you'd expect for single vs double base powders, but I should also point out that it is clearly not the same data set as posted by Uncle Ed; the values are not the same. For the powders I've actually used and recorded my own temperature data, they don't seem to be all that far off, as much I can tell. Because I am generally unsure of it's origin and validity, I choose not to propagate it further, that's all.

In the wider view, I'd say the chances are very good that powder temperature-sensitivity responses are NOT perfectly linear. In other words, velocities may well change more per degree within a given temperature range than another. Further, it could easily be possible that such values might differ in response to other variables, such as cartridge volume, bullet weight, barrel length, etc. So I'm not sure it is even possible (or feasible) to create such a chart that would be useful across a wide range of powders, cartridges, bullet, etc.

Upon returning to Omaha, NE a few years ago, where yearly temp swings are far larger than in San Diego, I have made an effort to chrono my loads routinely at different temperatures, especially when it's cool/cold in early spring/late fall and when it's very hot in July/August. I try to use the information more or less to set "bookends" for the low/high temperature extremes I'm likely to shoot in. If you have a feel for how many tenths of a grain you need to adjust a given load to keep velocity relatively constant at the low/hi bookends, it is relatively simple to make smaller adjustments during the season for smaller temperature fluctuations.

 

[CharlieNC]

I've shot a lot of CFE223 from 40 to 95 degF at our 300yd range, and never detected a difference in drop which would suggest a significant velocity change. Don't know about chrono, but I've not experienced accuracy/precision issues. Moral of the story - work up a good charge node and don't worry.