Found a newer study using AR comp, H335, CFE - interesting

[grayfox]

Found a study from Aug 2021, looking at powders for Service rifle competition. While it is for 223, it also shows some useful info on temperature behavior for some powders we use.
AR comp, varget, H335, CFE223, 8208, and H4895.
Temperature Sensitivity of Powders for .223 High Power Service Rifle (wlcastleman.com)

I would also note that the study is for the 223 cartridge, and my belief is that powder temperature sensitivity also can vary by cartridge, "fat" vs "thin" cases (ie, the nature of the powder column you have to burn), large vs smaller capacities, type of primer used. But it still provides some info. Particularly for the 77 gr bullet, as it is closer to our weights vs the 55.
Couple of takeaways I think I saw last night:
CFE is somewhat but not too sensitive from 68-32 deg, it is much more so for the higher temps.
AR comp actually increased MV as temp went down from 68-32 deg, which is a switch.
8208 fairly flat from 68-32 deg.

I zeroed in on the 68-32 part of the range b/c that's where I do most of my hunting, I don't normally go out when it's blazing hot or sub-zero.

[outbreaker]

Found a study from Aug 2021, looking at powders for Service rifle competition. While it is for 223, it also shows some useful info on temperature behavior for some powders we use.
AR comp, varget, H335, CFE223, 8208, and H4895.
Temperature Sensitivity of Powders for .223 High Power Service Rifle (wlcastleman.com)

I would also note that the study is for the 223 cartridge, and my belief is that powder temperature sensitivity also can vary by cartridge, "fat" vs "thin" cases (ie, the nature of the powder column you have to burn), large vs smaller capacities, type of primer used. But it still provides some info. Particularly for the 77 gr bullet, as it is closer to our weights vs the 55.
Couple of takeaways I think I saw last night:
CFE is somewhat but not too sensitive from 68-32 deg, it is much more so for the higher temps.
AR comp actually increased MV as temp went down from 68-32 deg, which is a switch.
8208 fairly flat from 68-32 deg.

I zeroed in on the 68-32 part of the range b/c that's where I do most of my hunting, I don't normally go out when it's blazing hot or sub-zero.

Wish they had gone from 90-32. I hunt like you in the 68-32 range, but load development is in the off season where 80-90 degrees is common.

[603 Country]

That was really interesting. Thanks much!

[jasper2408]

AR comp actually increased MV as temp went down from 68-32 deg, which is a switch.

Johnnys Reloading Bench did a temp test in one of his videos, using only Alliant powders, testing both the 223 and 308. With AR-Comp he got the same MV decrease with higher temps that your test showed, in both cartridges. The RL 15.5 powder MV decreased in the 223 cartridge as the temp went up but not in the 308.

About the 4:50 mark is where he starts showing the results.

https://www.youtube.com/watch?v=DfWdGD_ko9M

[StoneHendge]

Correct me if I'm wrong, but this study is almost entirely based upon output from some German dude's software (Quikload).

[grayfox]

Looks like he used QL to come up with initial loads for each powder but the results, MV and changes over temperature were from actual shooting.
Unless I'm missing something.
So if you get the load you're going to use from load data or from QL, that wouldn't matter. What matters are the actuals.

[Old Bob]

I wish AA2520 would have been included in his experiment. It was my go-to powder for 7.62/.308 Win in my M1A when I was shooting service rifle matches. I used 168gn Sierra HPBTs. I used it in .223 Rem as well with 75gn Sierras but don't recall it's accuracy. I need to find my reloading records. Never paid much mind to how they shot at different temps. As far as I can recall, my ammo with AA2520 was pretty consistent all year. I'd been planning to use it a lot with my Grendel & 6mm ARC. I have a bunch of AR-Comp I initially planned on using for .223 Rem but never got around to it. Grendel & ARC will get it now...

[StoneHendge]

Looks like he used QL to come up with initial loads for each powder but the results, MV and changes over temperature were from actual shooting.
Unless I'm missing something.
So if you get the load you're going to use from load data or from QL, that wouldn't matter. What matters are the actuals.

Your right - he wasn't very clear and if you click through to the charts, he shows it. I need to find some IMR 4166!

[myrifle]

Looks like he used QL to come up with initial loads for each powder but the results, MV and changes over temperature were from actual shooting.
Unless I'm missing something.
So if you get the load you're going to use from load data or from QL, that wouldn't matter. What matters are the actuals.

Ar-comp has become my almost go to powder for anything 123 grain or less weight in grendel.

I know some folks here have more years experience in handloading. But I have said many times here before. Let the rifle tell you what it wants.

A close second to ar-comp for me is h322, very very temp stable, nearly same case fill with nearly same velocity made per same powder charge.

[kmon]

I like 4166 for the Grendel, some say it is too bulky, never had that issue with it myself. The loads I did with it were for the 123gr SST and were more accurate and about the same speed as the factory loads in both my Grendels.

Been a while since I had QL but I do not remember a temperature parameter being an option. Might have been but I do not think it was. Predicted pressures were higher but velocities were very close as in 25fps or less off from measured velocities.

[StoneHendge]

Kmon, what charge are you maxing out in with 4166? I've had great success with Shooters World Precision despite the same sort of. poopooing, but it's even harder to find than Varget and H4340 these days

[DHD]

I wish AA2520 would have been included in his experiment. It was my go-to powder for 7.62/.308 Win in my M1A when I was shooting service rifle matches. I used 168gn Sierra HPBTs. I used it in .223 Rem as well with 75gn Sierras but don't recall it's accuracy. I need to find my reloading records. Never paid much mind to how they shot at different temps. As far as I can recall, my ammo with AA2520 was pretty consistent all year. I'd been planning to use it a lot with my Grendel & 6mm ARC. I have a bunch of AR-Comp I initially planned on using for .223 Rem but never got around to it. Grendel & ARC will get it now...

I used 2520 for the Grendel some time ago. I could get pretty spicy with the heavier weights (123's) and it didn't get silly in the SC heat.

I remember an article from Handloader (Powder Profiles?) describing the 3 iterations of it over the years. It seems that it was made in 3 different locations over time. The author called it "Camp Perry Powder".

[Dt219]

Ar-comp has become my almost go to powder for anything 123 grain or less weight in grendel.

I know some folks here have more years experience in handloading. But I have said many times here before. Let the rifle tell you what it wants.

A close second to ar-comp for me is h322, very very temp stable, nearly same case fill with nearly same velocity made per same powder charge.

I have some h322. In your opinion it’s a very good substitute to ar comp ? Why don’t more use it or try it with a 120 class bullet ? Thanks

[myrifle]

I have some h322. In your opinion it’s a very good substitute to ar comp ? Why don’t more use it or try it with a 120 class bullet ? Thanks

In my opinion it's a very good second choice too arcomp.

As too why others dont try it. I cant answer that for you.

[kmon]

Kmon, what charge are you maxing out in with 4166? I've had great success with Shooters World Precision despite the same sort of. poopooing, but it's even harder to find than Varget and H4340 these days

Sorry for late and not much info. I do not remember the load specifically now and that notebook was lost when my house was packed by someone else while i was unable to do it and lots got left behind. Accuracy was good though with it and about 100fps slower than Hornady factory on a close to 100 degree day from a 22inch barrel with 123gr SST bullets in Lapua brass. It was loaded to about the base of the neck for the most accurate load and had a little crunch but shot good and consistent , just wish I had my old data.