Did some powder temp sensitivity tests today, interesting results.

[Michael Eichele]

Powder: RL-25

Bullet: 200 ACCUBOND (30 cal)

Powder temp 1: 71 Degrees F.

Velocity 1: 3219
Velocity 2: 3227
Velocity 3: 3218

Avg Vel: 3220
ES 9 FPS
Std Dev 4.93

Powder temp 2: -2 degrees F.

Velocity 1: 3213
Velocity 2: 3189
Velocity 3: 3205

Avg Vel: 3200

ES 24
Std Dev 12.2


The difference here was 20 FPS on average. Note that the barrel was never -2 degrees and was room temperature. The POI was the same (center to center), group at 71 was 1.6" @ 300 yards. Group at -2 was 2.99" @ 300 yards

 

[Savagebien]

thanks for the info, powder temp sensitivity is very interesting to me and i try to stay on top of what my powder does in my rifle too!

 

[Lightvarmint]

Hello,

When I tested the RL line of powders in my 30 STW, 30/338 Lapua and 338 Lapua, I basically got the same data..... However, when the temps rose above the 90 degree mark, we really had trouble getting consistent groups and velocities from day to day...... Once we shifted to Hodgdon Extreme powders, then our issues disappeared. That is why I have some RL powder for sale as well as IMR.

Lightvarmint

 

[Shawn Carlock]

Meichele,

Interesting, when I tested the 338 Edge and 300 SMK with different powders including RL25 I got much different results. Around 170 fps difference with RL25 from 20 to 90 degrees. VV N560 90-100 fps. Accurate Mag Pro 140 fps. H1000 18-20 fps. It seems that every bullet, case, primer combo is effected differently by temp. The big thing that turned me off about RL25 was the lot to lot variations in powder. This is info everyone should know about their long range ammunition. Keep us updated.

 

[johndoe]

What kind of chronograph were you using?

 

[MachV]

No real surprize with the R25.....Especialy since the barrel was not cold too! Cant find my notes but I did a test on R15 and R22 many years ago, they did great as far as the powder being cold but the results where far more drastic with a cold barrel and the point of impact realy changed in the test gun I was useing....more than enough to miss a coyote @ 200 yards! Have also learned to keep them out of the sun and leaving them in a hot barrel too long, the powder takes being cold well but gets very irratic above 90º.
Have also learned to buy all Reloader powders in balk cause what you got aint what your gonna pick up next time!!!!!
I like and use a lot of Reloader powder but as with most other powders it does have its quwirks.

 

[Michael Eichele]

It seems that every bullet, case, primer combo is effected differently by temp. QUOTE]

That is exactly what I preach when people ask about sensitivity of a given powder.

 

[Michael Eichele]

Hello,

However, when the temps rose above the 90 degree mark, we really had trouble getting consistent groups and velocities from day to day

Not too concerned about that up here!

 

[Michael Eichele]

What kind of chronograph were you using?

"The Shooting Chrony"