CFE temp stability?

[Kodiak]

Shot 31.0 g cfe 223 with 123 SMK, Hornady brass and Fed 205m Ar primers. At 10am today the avg 5 shot velocity was 2517 with sd of 5 es 13, temp outside was roughly 65. Then shot later today, the exact same load, with avg 5 shot velocity of 2560. The temp outside was 80. Still had good sd of 6 and es of 11. Any thoughts as to why this would happen?

[biodsl]

CFE223 is my go-to powder but it's temperature sensitive. Collective wisdom on this forum is that it gains something under 2 fps per degree.

My load is 31.2 gr of CFE behind a 123 ELDM. I've chrono-ed it at various temps. Average velocities:
@40 degrees 2527
@60 degrees 2561
@80 degrees 2595

[Bobke]

Like CFE for velocity and flow through a powder measure, but temp sensitivity is a potential issue, but if reliably predictable accd to ambient temp, could be dialed into your dope to tell you where you need to be based on variable temps. Testing in various conditions only way to predict with certainty how to adjust for your barrel. Let us all know how that shakes out for you.

[Lemonaid]

Has anyone tested what happens to velocity/accuracy nodes at varied temperatures?

[StoneHendge]

Was the ammo outside between morning and afternoon or in the sun? Or in a hot car? It's the temp of the ammo - not the ambient temp that matters. But yes, I have found it to be extremely temp sensitive. When I lived in the mountains of CO, I used 30.8 grains at 2560 out of a 22". Ammo was probably stored in the mid sixties, kept in the shade at the range and the ambient temp never got much above 90. I'm in Phoenix now, keep my place at 79 and 30.4 grains gives me 2600 when it's 95-100 out. The old 30.8 grain load gave me around 2650 here with significant velocity variation and as you could guess, light ejector marks. These numbers are from different 8 pound jugs and I would attribute some of the difference to differing lots. The lot I'm using now is definitely faster.

[biodsl]

Has anyone tested what happens to velocity/accuracy nodes at varied temperatures?

I've never taken it to that level. Perhaps in 2021!

[Kodiak]

Great info. I have found that CFE sucks in the 223 but works pretty great in the Grendel. The ammo was not lying in a hot car, it was the ambient temp. It performed well . Multiple groups ranging from .5 to .8 inches with good sd. Hmm I have never use the temp sensitivity factory in my Strelok, guess Ill have to figure it out

Great idea to check velocity/accuracy nodes at different temps. I might have to work on that
Thanks gentlemen

[riuma]

I developed CFE223 loads for my CZ in Montana November. In Montana June they were beginning to flatten primers. In July, definitely flat.~Riuma

[Rosecrans1]

CFE223 just plain isn't temp stable. Period. I used it for awhile before seeing all kinds of temp deviation MV's.
I liked the speed I could get out of it and I had some pretty accurate loads but I want to be able to shoot what I load year round. Hence why I don't use it anymore.

[Bobke]

Ball powders may be the velocity kings, and have used a metric ton in Grendels, but have largely migrated to AR Comp, which tends to be more temp stable, has broader nodes and continues to yield very good accuracy across multiple platforms. Not CFE velocity, but consistent in variable TX temps from 90-100 six months of the year to 30-45 in the pitch of winter.

[bruceleroy]

My load is 30.5 grains behind a 123 ELD-M. Shot it last week atb95 degrees and it was hitting 2625 out of anb18" barrel. No flat primers or ejector marks. Super accurate too.

[StoneHendge]

Same loading session, 30.4 grains of CFE trickled onto a balance beam,123 Scenar, Lapua brass, GM205M. 22 inch JP barrel.

Stored at 79 degrees, 95 degree ambient: 2600 fps with 1/2 to 3/4 MOA 5 shot groups and low single digit sd a couple of weeks ago.

A cold front came through. This morning: storage 76, ambient temp 80. 2568 fps with 14 sd and groups blown out to 1 to 1.5 MOA.

Same days/times/temps/load session my 243 LBC with Chargemaster drop of Benchmark, 95 gr SMKs and virgin Hornady brass with a virgin neckdown ran 2760 and 2745, both with single digit sds. Groups a little tighter today but both sub MOA - load had been worked up in low 80s