Reloder 26, Temperature Stability Sensitivity Data

I like this chart. Let me make sure I understand it correctly; the numbers to the right of each powder represent the feet per second +/- per degree of temp? If this is not so, please explain. . .sorry. Thank you

I bring data.

I'm developing a load for my 300 Win Mag with the 220 gr Nosler Custom Competition.

At 30 degrees 72.8 grains of Reloder 26 shoots 2866 fps.
At 70 degrees 72.8 grains of Reloder 26 shoots 2904 and is over pressure.

At 70 degrees it takes 71.2 grains Reloder 26 to reach 2850 fps

At 30 degrees 69.4 grains of IMR 4955 shoots 2749 fps
At 70 degrees 69.3 grains of IMR 4955 shoots 2750 fps

Little different analysis since I'm solving for Optimal Barrel Time with QuickLOAD.

I have verified the 30 degree data with a Labradar.
The 70 degree data are from QuickLOAD
Not going to be 70 here for several months.

My data confirms Reloder 26 gives 100 fps higher velocity at the same pressure but loses around 1.0 fps per degree between 30 and 70 degrees.

Also looks as if IMR 4955 is very temperature stable but shoots approximately 100 fps slower than Reloder 26.

How can Quickload accurately predict temp swings when there are so many variables. I thought my test had flaws when it was 31 degrees out i let the rifle and ammo sit outside for 40 minutes. Shot 4 shots. Then put them in the truck with 75 degree heats for 40 minutes. Strapped on the magneto and shot 4 within 8 seconds of stepping out the truck the firing started. This gave me 40 degree change and about 11 FPS velocity loss on the colder rounds. Same temp stability with N570. Seems to be good from 30-70. I have read and not tested that over 80 is where it goes to ****..

Rhovee said:

How can Quickload accurately predict temp swings when there are so many variables. .

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I don't know the answer to that question, but I have found QuickLOAD predictions accurate in the past. The only way to know for sure is to shoot those loads over a chronograph at 70 degrees. I have done so at 30 degrees with my LabRadar. 70 degrees here in the mountains of Wyoming isn't happening anytime soon.

Hawk in WY said:

I don't know the answer to that question, but I have found QuickLOAD predictions accurate in the past. The only way to know for sure is to shoot those loads over a chronograph at 70 degrees. I have done so at 30 degrees with my LabRadar. 70 degrees here in the mountains of Wyoming isn't happening anytime soon.

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Well in Wyoming you could open a window and shoot from inside your house lol.

That's what I was thinking. Set up your lab radar and Keep everything warm and let her rip either from your truck or garage if your not around a lot of people.

bigedp51 said:

While the powder in question does not have the change in velocity for each degree of temperature change you can compare the double base powders against the Hodgdon's single base extreme powders.

Click on the image to enlarge.

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Where can the original of this chart be found?

jfseaman said:

Where can the original of this chart be found?

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It's on the net... See the link in post #6. The temp sensitivity data is gathered from various individuals testing results on the net also...

Barrelnut said:

It's on the net... See the link in post #6. The temp sensitivity data is gathered from various individuals testing results on the net also...

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Found it that time. It was under images in Google.

It is from the 6.5 Grendel forum. http://www.65grendel.com/forum/showthread.php?11196-Powder-Burn-Rates-and-Temp-Sensitivity

Looks like if I/we want an updated version it will have to be recreated in a spreadsheet and new data added.

Is it possible for pressure to go up when it gets colder out?

I ask this because earlier this winter I started with a new jug of 26 and hit pressure way before I did with the last jug. I assumed it was the difference between lots but maybe not. My initial load work up was done with temps in the 60's and 70's. The new lot was with temps in the single digits. With the new lot I hit pressure at 78.5 gr of 26 with the old lot i went up to 79.5 gr of 26 with zero pressure and in much warmer weather to boot.

Any way could temp have been a factor in this and it not necessarily been all from lot to lot inconsistencies?

Lot to lot variation for burn rate can vary up to 10%.

That will do it.

jfseaman said:

Where can the original of this chart be found?

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As stated above I found the image in Google images and the link did not lead back to its original web page and source.

I use R26 in everything I shoot because I'm a velocity freak. I shoot in temperatures from 10 - 90 degrees. My experience shows a fairly noticeable change from 30 - 50 degrees. I wish it were more stable for my use but I'll deal with the changes simply because it produces the highest velocities.

I'll be testing this powder over the next few weeks/months in my 6.5cm. Also some Nosler brass. The winchester brass I had was all over the place on water weight and brass weight up to 6gr difference. The Nosler was only 1.6gr. Being in texas im concerned about the high temp spike potential of this powder. While I dont hunt in 100 degrees I do shoot some in it. So next few weeks I'll have temps likely from 30 to 85 to test in and not long much hotter than that.