Is CFE223 temperature sensitive?

Last fall when it was cooler, I workrd up a load for my 308 Winchester using CFE223 and Sierra 168 Matchkings. I came up with a final load that was listed as 1.5 grains under max according to the book. This load was very accurate and I shot probably 30 of them through the rifle with no pressure signs.
Yesterday I took them to the range and fired 6 of them. Two of the last three blew out the primers but were not hard to extract. I checked the others and the primers were flattened.
I pulled the remaining rounds apart today and weighed the charges. All were right on the money for the load notes I made when I loaded them.
Accuracy was not as good as last fall.
The load data was as follows
Cases--Perfecta
Powder--47.5 grains CFE223
Primer--Federal standard LRP
Bullet-- 168 Sierra Matchking
OAL--2.855(bolt rifle seated .015 off the lands) This is a custom length for this rifle as measured using a Hornady bullet seating gauge.
Case volume appears to be the same as Winchester or Federal brass.

According to the Hodgdon data site, I am 1.5 grains under the max load for this powder/bullet combination as well as .055 longer on OAL.
Temperature when I worked up the load was 38-45 degrees F. The temp yesterday was 85-92 degrees.
Since this combination worked so well last fall in cooler weather, I have to think the powder was displaying temperature sensitivity.
There was no damage to the rifle and my other target load (different powder but otherwise same components) still shot excellent groups.
What are your thoughts?

I know they advertise some powders as not being affected by temp, but I've experienced the same thing as you and I've seen it on the chrony. I cant help but think they are only Less affected by temp. My $0.02

I only used it in the 223 with 55 grain loads in temps from -10 to 95. Same POI at 200 yards and no pressure issues.

I asked Hodgdon about it and they said it was not one of their 'extreme' powders and that there would be sensitivity to temperature. That said, they did not say by how much and I have not tested it since the powder was literally worthless as a propellant for me in my rifles.

The test is quite easy though. Cook some rounds on the sun-lit dashboard and put some others in a cooler with ice and put them over a chronograph and observe primers/extraction effort...

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Originally Posted by McFred

The test is quite easy though. Cook some rounds on the sun-lit dashboard and put some others in a cooler with ice and put them over a chronograph and observe primers/extraction effort...

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I believe I will give that a try in the future. It will be an easy way to find out and I have all the necessary equipment.

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Originally Posted by tazman

I believe I will give that a try in the future. It will be an easy way to find out and I have all the necessary equipment.

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Let us know your results I use a lot of CFE 223 and would like to know

Well your experience/ experiment pretty much proves that it is a bit unstable across the temperature spectrum.

I did the same exact thing with BLC2 in .223 years ago. I had a great safe load that was perfectly accurate in the Spring. Come mid summer I had flat and pierced primers with the same exact lot of reloads.

My memory might be fuZzy but I thought CFE223 was BLC2 with the copper binding additives increased. Wc844 and wc846 are bulk H335 and BLC2. All one family with a little burn rate spectrum spread.

I'm watching this one.....

This is a tough one, Taz! I'm thinking it had to be something else, but I honestly have no idea what! You sure there couldn't have been a mixup in the ammo? Happened to me once. Was using an '03 Spfld sporter, and first round blew the primer pocket out to well over 1/4" diameter! Extraction was very normal, too! Who says those old war horses aren't strong?

Wish I had an idea, but this one leves me blank.

I tested CFE223 today in 2 different cartridges(223 and 308) due to the hot weather(92 degrees). It made it easier to get the ammunition hot enough to make a difference.
I left half the ammo in the car on the dash while I was shooting pistol for an hour indoors and then ran it through the chrono. The other half was in a plastic bag, in ice, inside a cooler until I took it out an immediately fired it over the chrono.
I loaded all the ammo this morning before the trip to the range using matched cases and weighed charges. All bullets were Sierra Matchkings. 69 grains for the 223 and 168 grains for the 308.
I shot my normal load of BLC-2 over the chrono just as a standard to see how the numbers came out since it shoots well in these rifles.
The rifles were Savage model 10 fcp-sr in 308 win(long barrel version) and a Savage model 10 with a varmint barrel(factory).
I can't give precise temperatures, but the hot ammo was between 95 and 100 degrees. The cold ammo was at 32 degrees or a bit below.
I loaded the 223 at 24 grains of CFE223 and the 308 at 45 grains of CFE223. My standard loading for BLC-2 is 25.5 grains for 223 and 45.5 grains for 308.
The test results are as follows.
CFE223 in 223 hot temp 2733 average extreme spread 25
CFE223 in 223 cold temp 2663 average extreme spread 59
CFE223 in 308 hot temp 2661 average extreme spread 81
CFE223 in 308 cold temp 2641 average extreme spread 43
BLC-2 in 223 average 2620 extreme spread 21
BLC-2 in 308 average 2691 extreme spread 25

The BLC-2 loads group better in my rifles but not by a lot.
The difference in point of impact at 100 yards was 1/2 inch(vertical) in the 223 between the hot and cold loads.
There was no real difference in point of impact at 100 yards in the 308.
In 223, I lost 70fps between the hot and cold ammo. This seems to be fairly significant but may not be. I don't have enough test results with other powders.
In 308, I only lost 20 fps.
The big issue was the extreme spreads with CFE223 in both cartridges. They were significantly higher than the spreads with BLC-2.

I need to play with the powder charge in the 223 to get the velocity to match the BLC-2 load and see how that performs. I don't know if it will matter but the extreme spread might improve.

Very interesting results Tazman. I am becoming more and more a fan of the "extreme" powders for this very reason.
My brother and I ran into a similar problem loading for his .260 using IMR4350
He ended up working up a great load using H4831 instead.
Thanks for the test results!

Thanks for the test results. I just found CFE223, and I'll be watching for the pressure signs you experienced.

I have been using it in a 222 Rem with 53 Smks, and it is working very well for F-class @ 300 yards. There is no sense weighing, as the powder measure drops right on the money. Using it in the 222, it is impossible to overcharge and gives great velocities.


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Thanks for the very complete report. I was wondering if the gun / barrel was cooled any between groups.

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Originally Posted by 725

Thanks for the very complete report. I was wondering if the gun / barrel was cooled any between groups.

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It was cooled for a couple of minutes between groups. I switched back and forth between guns after each group.
I ran a patch down the barrel with some Hoppes on it to get powder fouling out then fired a single fouling shot for consistency.
The fouling shot was faster than the rest of the shots in every case(sometimes significantly) so I discarded it in the results. Apparently having the barrel lubed makes a lot of difference in velocity for one shot.