Powder Stability.

[jrock]

I've charted IMR 4350 in my .243 and get about 2 fps/deg and similar with my 7RM and IMR 7828 and 7828 SSC. I've played around with CFE 223 and found it's sensitivity to high for me to use throughout the year. I tested up some in a .204 at 75 deg and was getting low velocities and no pressure signs. Went out on a 95 deg day with the same test rounds and blew the primers out on the first two shots. Haven't bothered with it since.

 

[jpretle]

I would be interested in the numbers for RL26, if someone has any.

 

[6.506ai]

Anyone done 2213sc?

 

[Clucknmoan]

I would be interested in the numbers for RL26, if someone has any.

+1

 

[SimpleMind949]

Here's three powders in three different cartridges. Velocity was recorded over duplicate chronographs (Oehler 33 & Pact PC2) or triplicate chronographs (Oehler 33 & Pact PC2 & Oehler 35P) run concurrently with each bullet fired.
Tract 1 is Retumbo in a 7mm Rem Mag with a 168gr Berger VLD. Barrel length = 24 3/8".
Tract 2 is IMR 7828 in a 300 Win Mag with a 210gr Berger VLD. Barrel length = 25 1/2".
Tract 3 is H1000 in a 280 RCBS Improved with a 162gr Hornady Amax. Barrel length = 28".

I know the H1000 speeded up as the temperatures dropped. Don't ask me why. Best I can figure is they've treated the Hodgdon Extreme powders to increase burn rate as temperatures fall. In this case MV increased with this lot of H1000 with decreasing temperatures.

Notice the big differences between the two Hodgdon Extreme powders and IMR 7828.

It looks like the data you posted is not showing, is there anyway you could repost or send me the information on the Retumbo?

Thank you!

 

[Rhovee]

I worked up a load for my 6.5wsm using rl26. In 85 degree weather I was shooting 3060-3070. In 39 degree weather I am shooting 3040-3050.

 

[Bbear]

Worked up a load in 45 degree spring temps for my 25-06 with RL-19 and 110 AB's. Speed was a bit low - only 2900. Fast forward to summer time here in Texas with temps in the low 100's and the same loads locked up the action. Took a rubber mallet to get the bolt to open.
The remainder of the RL-19 fertilized my garden.
Moved on to 7977 and raised the speed, improved the accuracy and reduced the ES to near single digits. No significant change in groups or speed with changes in temps from the summer load to 'winter'.

 

[tim_w]

Reloader 33 0.58 fps/°F


My guess is based on make up that 26 should come in very close to this maybe a .1 higher.

 

[AZShooter]

As long as this old thread is alive again...I must say it is interesting and worthy of saving in my documents file.

The manufacturers of these powders have interesting phrases to describe the powder's insensitivity to temperature changes.

I have to wonder about the accuracy of IMR 8208 BR as .59 per degree. It is billed as being "virtually no change in velocity at temperatures ranging from -40 degrees F to 165+ degrees F". I would think it would be similar to the low number of Varget. Hodgdon also says Varget "is insensitive to hot and cold temperatures" and Backwoods83's list says .19 per degrees, the lowest on this chart.


Tim: RL-17 (alliant: "Consistent maximum velocity in extreme weather conditions") has same makeup as RL-33 ("Its double base gives it consistent performance across temperature and humidity extremes") and RL-26 ("Controlled temperature stability") but the report has RL-17 at 1.42 per degree. You said RL-33 is .58 per degree which has it as one of the powders with the least change. Wonder what RL-26 will actually show?

 

[Rhovee]

I am also curious how primers would effect temp stability. For instance, RL26 is never mentioned in Aliant's load manual without a FED 215 primer. I was using a Fed 210 based on a smaller case. I talked to a very good gun smith who uses RL 26 a lot, and he mentioned the powder needed a magnum primer. I am going to test temp sensitivity with the magnum primer and see what happens.

 

[tim_w]

I think there is some variation with primer. Has it ever been considered the effect temp has on the primer compound mixture itself??

About RL26 vs RL33 if you look a post#20 and average it come out to be .43 per degree between 39 and 85. Overwhelmingly people have reported RL33 as quite temp stable so this all looks in line to me.

Most everyone knows that RL17 is almost useless if you need it to work at more tan 10-20 degrees different ambient temp. IMO RL19 seems to fit in this group as well. Not sure how close exactly it is but its bad as has also been reflected by post #21

While Alliant certainly is hit or miss with temp stability one thing is for sure, many of their powders seem to produce the highest vel for a given burn rate range. Rel7 Rel10, Rel 17 Rel 26, Rel33 are ones that stand out for me.

 

[Lonewolf74]

Anyone possibly have some data for VV N570?

Thought I read in a post here a while back that a couple guy's where getting RL26 speeds with much better stability with the N570. So I'd like to test some but I wanna get a good idea first with how expensive the N570 is

 

[Rhovee]

I use N570 in my 28 Nosler and have tested it from 85-39 degree's. No change in FPS. Shawn Carlock did a really good temp testing on it as well. Came to the same conclusion. Very temp stable. Expensive, but worth it.

 

[Bowfishn]

There is a thread dedicated to RL26 and various Cartridges.

https://www.longrangehunting.com/th...ty-of-alliant-reloder-26.187256/#post-1321247