For those trying to get a handle on this issue, there is a pretty good article detailing an experiment comparing IMR Enduron vs Hodgdon Extreme powders on the PRB or Precision Rifle Blog under the Ammo & Handloading category. Since it used H4350 and Varget, 2 of my favorites, it sucked me in.
Thanks to the Powder Valley guys for pointing it out.
It should please the most anal of you.

Thanks for pointing that out. It's good to have options, but H4350 and Varget continue to be reliable. All four powders did pretty well though, considering they were ramped all the way up to 140 degrees.

Published 6/19/2016. Guess just being Just 3 years old makes it new, refreshing and unique.

Swifty,

What is the source of that info?

I've read that CFE223 and PP2000MR were similar if not the same powder. This chart shows them to be grossly different regarding temp stability.

And, I've read that TAC and Big Game are a bit more temp stable than Hunter and Magnum. This chart has that relationship reversed.

DF

Swifty, You have not added much to the conversation other than a condescending attitude.
It was a pretty sound "real world" test with all things being equal, excepting 1 variable.
Without some qualifications, your list may just be more internet fiction.
Was hoping for an intelligent conversation.

I checked out the entire article on the Precision Rifle Blog, and found the tests were made by only heating and cooling the ammo, not the entire rifle, which in my own temp-tests has often affected results. Also, the "cold" tests were made at 25 degrees, which generally isn't cool enough to affect the velocity of most modern powders very much, compared to firing in "normal" temperatures of, say, 50-80 degrees. Since I'm primarily a hunter, not a target shooter, and do most of my hunting in Montana, I'm generally more concerned with real cold, so test at zero degrees F., and sometimes even 20 degrees below--by shooting in those temperatures.

However, also do some summer prairie dog shooting in hot weather, occasionally up around 100 degrees, where barrels get much hotter, So do my "hot" tests on days that get as close to 100 as possible (they don't occur every summer, but 90+ is pretty common) and then "greenhouse" the ammo inside a clear plastic bag with a thermometer to around 120 degrees. Then I shoot chronograph the loads by shooting repeatedly to heat up the barrel, just like it often happens in PD shooting, leaving each round in the chamber long enough to heat up even more.

My results with some of the same powders listed in the PRB tests varied considerably from theirs.

I question these all inclusive charts. There are just too many variables involved to make such blanket statements.

DF

The only Enduron powder I use is 7977 for 7mm, but am concerned about its "copper fouling eliminator" feature which I don't subscribe to.

I use it sparingly for really cold or hot weather, really long range...barn shooting.

I know CFE223 has pretty terrible temp stability in the 22-250.
RL-17 isnt much better in the 300 WSM.

This seems to me to be an odd thing to be skeptical about. The de-coppering agents have been tested thoroughly by several military armories and the powder manufacturers. It does leave it's own residue but it is very easy to remove, far easier than copper or carbon. The only down side I can think of is if it attacks brass or bullets, but since it is only effective when ignited this is not likely to occur. But many people were skeptical of smokeless powder when it was first developed.

The charts are nice for temperature sensitivity comparisons but the change is seldom consistent or linear or if it is then for only a limited temperature range.
One thing it just keeps getting better with each new development in powder technology.

WHY would you want to *R E M O V E* copper when the next bullet does it for you and then replaces it giving you COPPER EQUILIBRIUM?

Study up.

It's not the ambient temperature that matters.

The mechanism of loss of muzzle velocity is not the initial temperature of the powder. It is the amount of heat energy that cooler steel, lead, and brass "rob" out of the propulsion gas.

Temperature of the chamber matters most. Temperature of the ammunition matters about 1/3 as much as the chamber. Ambient temperature only matters because it is one factor that affects barrel and ammunition temperature.

just got an advert from Powder Valley, winchester has a new ball powder they call 6.5 StaBALL

supposed to be the first ball powder that is temp insensitive, and is a good fit (velocity/pressure wise) for the Creedmoor



https://www.powdervalleyinc.com/product/winchester-staball-6-5/?

Interesting. No data for it yet that I’ve seen though.

John

Ahhh, that is not how copper equilibrium works.

Copper equilibrium? Please enlighten me?

With out de-copper agents the fouling is additive and linear, with it is removed at almost an equal rate as it is being deposited. If this is correct wouldn't the latter be more consistent? Or do I have it wrong? These are my assumptions and we all know about assumptions.

Along with temperature insensitivity the copper build up will eventually increase pressure and affect accuracy, no? So temp stability and less fouling create more uniform loads? More assumptions.

Y'all check out the Hodgdon reloading data center on their site. There's some data for this new powder for the 6.5 Creed, at the very least. There may be more than that, but I didn't search real hard for any more.


http://www.hodgdonreloading.com/data/rifle

The Hodgdon site shows it working for the 7mm-08. Loads getting a 140 gr up to 2900 fps sound interesting.

If the claims are true about the stability than StaBALL 6.5 looks promising for the 7mm-08. Their data is showing some impressive speeds.

120 @ 3200
130 @ 3125
140 @ 3000
150 @ 2900
160 @ 2825
I ordered some from powder valley to try. Always fun to tinker.